diff --git a/app/src/main/java/com/umc/edison/data/datasources/BubbleLocalDataSource.kt b/app/src/main/java/com/umc/edison/data/datasources/BubbleLocalDataSource.kt
index be229578f..459780d86 100644
--- a/app/src/main/java/com/umc/edison/data/datasources/BubbleLocalDataSource.kt
+++ b/app/src/main/java/com/umc/edison/data/datasources/BubbleLocalDataSource.kt
@@ -5,7 +5,7 @@ import com.umc.edison.data.model.bubble.BubbleEntity
 interface BubbleLocalDataSource {
     // CREATE
     suspend fun addBubbles(bubbles: List<BubbleEntity>)
-    suspend fun addBubble(bubble: BubbleEntity) : BubbleEntity
+    suspend fun addBubble(bubble: BubbleEntity, userId: String? = null) : BubbleEntity
 
     // READ
     suspend fun getAllActiveBubbles(): List<BubbleEntity>
@@ -24,6 +24,7 @@ interface BubbleLocalDataSource {
     suspend fun trashBubbles(bubbles: List<BubbleEntity>)
     suspend fun markAsSynced(bubble: BubbleEntity)
     suspend fun syncBubbles(bubbles: List<BubbleEntity>)
+    suspend fun linkGuestBubblesToUser(userId: String)
 
     // DELETE
     suspend fun deleteBubbles(bubbles: List<BubbleEntity>)
diff --git a/app/src/main/java/com/umc/edison/data/repository/BubbleRepositoryImpl.kt b/app/src/main/java/com/umc/edison/data/repository/BubbleRepositoryImpl.kt
index 615de050b..aee32e485 100644
--- a/app/src/main/java/com/umc/edison/data/repository/BubbleRepositoryImpl.kt
+++ b/app/src/main/java/com/umc/edison/data/repository/BubbleRepositoryImpl.kt
@@ -7,6 +7,7 @@ import com.umc.edison.data.datasources.BubbleRemoteDataSource
 import com.umc.edison.data.model.bubble.ClusteredBubbleEntity
 import com.umc.edison.data.model.bubble.KeywordBubbleEntity
 import com.umc.edison.data.model.bubble.toData
+import com.umc.edison.data.token.TokenManager
 import com.umc.edison.domain.DataResource
 import com.umc.edison.domain.model.bubble.Bubble
 import com.umc.edison.domain.model.bubble.ClusteredBubble
@@ -19,7 +20,8 @@ import javax.inject.Inject
 class BubbleRepositoryImpl @Inject constructor(
     private val bubbleLocalDataSource: BubbleLocalDataSource,
     private val bubbleRemoteDataSource: BubbleRemoteDataSource,
-    private val resourceFactory: FlowBoundResourceFactory
+    private val resourceFactory: FlowBoundResourceFactory,
+    private val tokenManager: TokenManager
 ) : BubbleRepository {
     // CREATE
     override fun addBubbles(bubbles: List<Bubble>): Flow<DataResource<Unit>> =
@@ -41,7 +43,9 @@ class BubbleRepositoryImpl @Inject constructor(
 
     override fun addBubble(bubble: Bubble): Flow<DataResource<Bubble>> =
         resourceFactory.sync(
-            localAction = { bubbleLocalDataSource.addBubble(bubble.toData()) },
+            localAction = {
+                bubbleLocalDataSource.addBubble(bubble.toData())
+            },
             remoteSync = {
                 val newBubble = bubbleLocalDataSource.getActiveBubble(bubble.id)
                 bubbleRemoteDataSource.syncBubble(newBubble)
@@ -193,6 +197,10 @@ class BubbleRepositoryImpl @Inject constructor(
             }
         )
 
+    override suspend fun linkGuestBubblesToUser(userId: String) {
+        bubbleLocalDataSource.linkGuestBubblesToUser(userId)
+    }
+
     // DELETE
     override fun deleteBubbles(bubbles: List<Bubble>): Flow<DataResource<Unit>> =
         resourceFactory.sync(
@@ -212,7 +220,8 @@ class BubbleRepositoryImpl @Inject constructor(
                 }
             },
             onRemoteSuccess = { deletedBubbles ->
-               val localBubbles = deletedBubbles.map { remote -> bubbleLocalDataSource.getRawBubble(remote.id) }
+                val localBubbles =
+                    deletedBubbles.map { remote -> bubbleLocalDataSource.getRawBubble(remote.id) }
                 bubbleLocalDataSource.deleteBubbles(localBubbles)
             }
         )
diff --git a/app/src/main/java/com/umc/edison/data/repository/UserRepositoryImpl.kt b/app/src/main/java/com/umc/edison/data/repository/UserRepositoryImpl.kt
index b988be850..3950b7cf5 100644
--- a/app/src/main/java/com/umc/edison/data/repository/UserRepositoryImpl.kt
+++ b/app/src/main/java/com/umc/edison/data/repository/UserRepositoryImpl.kt
@@ -9,6 +9,7 @@ import com.umc.edison.data.token.TokenManager
 import com.umc.edison.domain.DataResource
 import com.umc.edison.domain.model.identity.Identity
 import com.umc.edison.domain.model.user.User
+import com.umc.edison.domain.repository.BubbleRepository
 import com.umc.edison.domain.repository.UserRepository
 import kotlinx.coroutines.flow.Flow
 import javax.inject.Inject
@@ -17,12 +18,16 @@ class UserRepositoryImpl @Inject constructor(
     private val userRemoteDataSource: UserRemoteDataSource,
     private val resourceFactory: FlowBoundResourceFactory,
     private val tokenManager: TokenManager,
+    private val bubbleRepository: BubbleRepository
 ) : UserRepository {
-    // CREATE
+
     override fun googleLogin(idToken: String): Flow<DataResource<User>> = resourceFactory.remote(
         dataAction = {
             val userWithToken: UserWithTokenEntity = userRemoteDataSource.googleLogin(idToken)
+            val userEmail = userWithToken.user.email
             tokenManager.setToken(userWithToken.accessToken, userWithToken.refreshToken)
+            tokenManager.saveUserId(userEmail)
+            bubbleRepository.linkGuestBubblesToUser(userEmail)
             userWithToken
         }
     )
@@ -39,17 +44,19 @@ class UserRepositoryImpl @Inject constructor(
                     nickname = nickname,
                     identity = identity.map { it.toData() }
                 )
+            val userEmail = userWithToken.user.email
             tokenManager.setToken(userWithToken.accessToken, userWithToken.refreshToken)
+            tokenManager.saveUserId(userEmail)
+            bubbleRepository.linkGuestBubblesToUser(userEmail)
+
             userWithToken
         }
     )
 
-
-
     // READ
     override fun getLogInState(): Flow<DataResource<Boolean>> = resourceFactory.local(
         dataAction = {
-            tokenManager.loadAccessToken()?.isNotEmpty()
+            tokenManager.loadAccessToken()?.isNotEmpty() == true
         }
     )
 
diff --git a/app/src/main/java/com/umc/edison/data/token/TokenManager.kt b/app/src/main/java/com/umc/edison/data/token/TokenManager.kt
index 7c8987ca6..40086550b 100644
--- a/app/src/main/java/com/umc/edison/data/token/TokenManager.kt
+++ b/app/src/main/java/com/umc/edison/data/token/TokenManager.kt
@@ -17,11 +17,13 @@ class TokenManager @Inject constructor(
         applicationScope.launch {
             loadAccessToken()
             loadRefreshToken()
+            loadUserId()
         }
     }
 
     private var cachedAccessToken: String? = null
     private var cachedRefreshToken: String? = null
+    private var cachedUserId: String? = null
 
     override fun getAccessToken(): String? {
         if (cachedAccessToken == null) {
@@ -37,9 +39,17 @@ class TokenManager @Inject constructor(
         return cachedRefreshToken
     }
 
+    suspend fun getUserId(): String? {
+        if (cachedUserId != null) {
+            return cachedUserId
+        }
+        return loadUserId()
+    }
+
     override fun clearCachedTokens() {
         cachedAccessToken = null
         cachedRefreshToken = null
+        cachedUserId = null
     }
 
     override fun setCachedTokens(accessToken: String, refreshToken: String?) {
@@ -54,6 +64,8 @@ class TokenManager @Inject constructor(
         return token
     }
 
+
+
     suspend fun loadRefreshToken(): String? {
         val token = prefDataSource.get(REFRESH_TOKEN_KEY, "")
         cachedRefreshToken = token.ifEmpty { null }
@@ -61,6 +73,17 @@ class TokenManager @Inject constructor(
         return token
     }
 
+    suspend fun loadUserId(): String? {
+        val id = prefDataSource.get(USER_ID_KEY, "")
+        cachedUserId = id.ifEmpty { null }
+        return cachedUserId
+    }
+
+    suspend fun saveUserId(userId: String) {
+        cachedUserId = userId
+        prefDataSource.set(USER_ID_KEY, userId)
+    }
+
     suspend fun setToken(accessToken: String, refreshToken: String? = null) {
         cachedAccessToken = accessToken
         prefDataSource.set(ACCESS_TOKEN_KEY, accessToken)
@@ -71,14 +94,17 @@ class TokenManager @Inject constructor(
     }
 
     suspend fun deleteToken() {
-        cachedAccessToken = null
-        cachedRefreshToken = null
+        clearCachedTokens()
+
         prefDataSource.remove(ACCESS_TOKEN_KEY)
         prefDataSource.remove(REFRESH_TOKEN_KEY)
+        prefDataSource.remove(USER_ID_KEY)
     }
 
+
     companion object {
         private const val ACCESS_TOKEN_KEY = "access_token"
         private const val REFRESH_TOKEN_KEY = "refresh_token"
+        private const val USER_ID_KEY = "user_id"
     }
 }
diff --git a/app/src/main/java/com/umc/edison/domain/repository/BubbleRepository.kt b/app/src/main/java/com/umc/edison/domain/repository/BubbleRepository.kt
index 0efd09170..cd058f2c6 100644
--- a/app/src/main/java/com/umc/edison/domain/repository/BubbleRepository.kt
+++ b/app/src/main/java/com/umc/edison/domain/repository/BubbleRepository.kt
@@ -26,6 +26,7 @@ interface BubbleRepository {
     fun recoverBubbles(bubbles: List<Bubble>): Flow<DataResource<Unit>>
     fun updateBubbles(bubbles: List<Bubble>): Flow<DataResource<Unit>>
     fun updateBubble(bubble: Bubble): Flow<DataResource<Bubble>>
+    suspend fun linkGuestBubblesToUser(userId: String)
 
     // DELETE
     fun deleteBubbles(bubbles: List<Bubble>): Flow<DataResource<Unit>>
diff --git a/app/src/main/java/com/umc/edison/local/datasources/BaseLocalDataSourceImpl.kt b/app/src/main/java/com/umc/edison/local/datasources/BaseLocalDataSourceImpl.kt
index 1dff639a9..6d425f2d3 100644
--- a/app/src/main/java/com/umc/edison/local/datasources/BaseLocalDataSourceImpl.kt
+++ b/app/src/main/java/com/umc/edison/local/datasources/BaseLocalDataSourceImpl.kt
@@ -25,7 +25,10 @@ open class BaseLocalDataSourceImpl<T : BaseSyncLocal>(
 
     // UPDATE
     suspend fun update(entity: T, tableName: String, isSynced: Boolean = false) {
-        val query = SimpleSQLiteQuery("SELECT * FROM $tableName WHERE id = '${entity.uuid}'")
+        val query = SimpleSQLiteQuery(
+            "SELECT * FROM $tableName WHERE id = ?",
+            arrayOf(entity.uuid)
+        )
         baseDao.getById(query)?.let {
             entity.createdAt = it.createdAt
             entity.updatedAt = Date()
@@ -36,7 +39,10 @@ open class BaseLocalDataSourceImpl<T : BaseSyncLocal>(
 
     suspend fun markAsSynced(tableName: String, id: String) {
         val date = Date()
-        val query = SimpleSQLiteQuery("UPDATE $tableName SET is_synced = 1, updated_at = '$date' WHERE id = '$id'")
+        val query = SimpleSQLiteQuery(
+            "UPDATE $tableName SET is_synced = 1, updated_at = ? WHERE id = ?",
+            arrayOf(date.time, id)
+        )
         baseDao.markAsSynced(query)
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/umc/edison/local/datasources/BubbleLocalDataSourceImpl.kt b/app/src/main/java/com/umc/edison/local/datasources/BubbleLocalDataSourceImpl.kt
index c808ac237..3f1cd22a8 100644
--- a/app/src/main/java/com/umc/edison/local/datasources/BubbleLocalDataSourceImpl.kt
+++ b/app/src/main/java/com/umc/edison/local/datasources/BubbleLocalDataSourceImpl.kt
@@ -3,6 +3,7 @@ package com.umc.edison.local.datasources
 import android.icu.util.Calendar
 import com.umc.edison.data.datasources.BubbleLocalDataSource
 import com.umc.edison.data.model.bubble.BubbleEntity
+import com.umc.edison.data.token.TokenManager
 import com.umc.edison.local.model.BubbleLocal
 import com.umc.edison.local.model.toLocal
 import com.umc.edison.local.room.RoomConstant
@@ -17,53 +18,75 @@ class BubbleLocalDataSourceImpl @Inject constructor(
     private val bubbleDao: BubbleDao,
     private val labelDao: LabelDao,
     private val bubbleLabelDao: BubbleLabelDao,
-    private val linkedBubbleDao: LinkedBubbleDao
+    private val linkedBubbleDao: LinkedBubbleDao,
+    private val tokenManager: TokenManager
 ) : BubbleLocalDataSource, BaseLocalDataSourceImpl<BubbleLocal>(bubbleDao) {
 
     private val tableName = RoomConstant.getTableNameByClass(BubbleLocal::class.java)
 
-    // CREATE
+    override suspend fun linkGuestBubblesToUser(userId: String) {
+        bubbleDao.linkGuestBubblesToUser(userId)
+    }
+
+    // --- CREATE ---
     override suspend fun addBubbles(bubbles: List<BubbleEntity>) {
+        val userId = tokenManager.getUserId()
         bubbles.forEach { bubble ->
-            addBubble(bubble)
+            addBubble(bubble, userId)
         }
     }
 
-    override suspend fun addBubble(bubble: BubbleEntity): BubbleEntity {
-        val id = insert(bubble.toLocal())
-        val insertedBubble = bubble.copy(id = id)
+    override suspend fun addBubble(bubble: BubbleEntity, userId: String?): BubbleEntity {
+        val targetUserId = userId ?: tokenManager.getUserId()
+        val localBubble = BubbleLocal(
+            uuid = bubble.id,
+            userId = targetUserId,
+            title = bubble.title,
+            content = bubble.content,
+            mainImage = bubble.mainImage,
+            isSynced = bubble.isSynced,
+            isTrashed = bubble.isTrashed,
+            isDeleted = bubble.isDeleted,
+            createdAt = bubble.createdAt,
+            updatedAt = bubble.updatedAt,
+            deletedAt = bubble.deletedAt
+        )
 
-        addBubbleLabel(insertedBubble)
-        addLinkedBubble(insertedBubble)
+        val id = insert(localBubble)
 
+        val insertedBubble = bubble.copy(id = id)
+        addBubbleLabel(insertedBubble)
         return getActiveBubble(insertedBubble.id)
     }
 
-    // READ
+    // --- READ ---
     override suspend fun getAllActiveBubbles(): List<BubbleEntity> {
-        val localBubbles: List<BubbleLocal> = bubbleDao.getAllActiveBubbles()
-
+        val userId = tokenManager.getUserId()
+        val localBubbles: List<BubbleLocal> = bubbleDao.getAllActiveBubbles(userId)
         return convertLocalBubblesToBubbleEntities(localBubbles)
     }
 
     override suspend fun getAllRecentBubbles(dayBefore: Int): List<BubbleEntity> {
+        val userId = tokenManager.getUserId()
         val timestampLimit = Calendar.getInstance().apply {
             add(Calendar.DAY_OF_YEAR, -dayBefore)
         }.time.time
-        val localBubbles: List<BubbleLocal> = bubbleDao.getAllRecentBubbles(timestampLimit)
+        val localBubbles: List<BubbleLocal> = bubbleDao.getAllRecentBubbles(timestampLimit, userId)
 
         return convertLocalBubblesToBubbleEntities(localBubbles)
     }
 
     override suspend fun getAllTrashedBubbles(): List<BubbleEntity> {
-        val deletedBubbles: List<BubbleLocal> = bubbleDao.getAllTrashedBubbles()
+        val userId = tokenManager.getUserId()
+        val deletedBubbles: List<BubbleLocal> = bubbleDao.getAllTrashedBubbles(userId)
 
         return convertLocalBubblesToBubbleEntities(deletedBubbles)
     }
 
     override suspend fun getActiveBubble(id: String): BubbleEntity {
-        val bubble = bubbleDao.getActiveBubbleById(id)?.toData()
-            ?: throw IllegalArgumentException("Bubble with id $id not found")
+        val userId = tokenManager.getUserId()
+        val bubble = bubbleDao.getActiveBubbleById(id, userId)?.toData()
+            ?: throw IllegalArgumentException("Bubble with id $id not found for current user")
 
         val result = bubble.copy(
             labels = labelDao.getAllActiveLabelsByBubbleId(id).map { it.toData() },
@@ -75,7 +98,8 @@ class BubbleLocalDataSourceImpl @Inject constructor(
     }
 
     override suspend fun getRawBubble(id: String): BubbleEntity {
-        val bubble = bubbleDao.getRawBubbleById(id)?.toData()
+        val userId = tokenManager.getUserId()
+        val bubble = bubbleDao.getRawBubbleById(id, userId)?.toData()
             ?: throw IllegalArgumentException("Bubble with id $id not found")
 
         val result = bubble.copy(
@@ -88,27 +112,29 @@ class BubbleLocalDataSourceImpl @Inject constructor(
     }
 
     override suspend fun getBubblesByLabelId(labelId: String): List<BubbleEntity> {
-        val localBubbles: List<BubbleLocal> = bubbleDao.getBubblesByLabelId(labelId)
+        val userId = tokenManager.getUserId()
+        val localBubbles: List<BubbleLocal> = bubbleDao.getBubblesByLabelId(labelId, userId)
         return convertLocalBubblesToBubbleEntities(localBubbles)
     }
 
     override suspend fun getBubblesWithoutLabel(): List<BubbleEntity> {
-        val localBubbles: List<BubbleLocal> = bubbleDao.getBubblesWithoutLabel()
+        val userId = tokenManager.getUserId()
+        val localBubbles: List<BubbleLocal> = bubbleDao.getBubblesWithoutLabel(userId)
         return convertLocalBubblesToBubbleEntities(localBubbles)
     }
 
     override suspend fun getSearchBubbleResults(query: String): List<BubbleEntity> {
-        val localBubbles: List<BubbleLocal> = bubbleDao.getSearchBubbles(query)
+        val userId = tokenManager.getUserId()
+        val localBubbles: List<BubbleLocal> = bubbleDao.getSearchBubbles(query, userId)
         return convertLocalBubblesToBubbleEntities(localBubbles)
     }
 
     override suspend fun getUnSyncedBubbles(): List<BubbleEntity> {
         val localBubbles: List<BubbleLocal> = getAllUnSyncedRows(tableName)
-
         return convertLocalBubblesToBubbleEntities(localBubbles)
     }
 
-    // UPDATE
+    // --- UPDATE ---
     override suspend fun updateBubbles(bubbles: List<BubbleEntity>) {
         bubbles.forEach { bubble ->
             updateBubble(bubble)
@@ -125,6 +151,10 @@ class BubbleLocalDataSourceImpl @Inject constructor(
         addBubbleLabel(bubble)
         addLinkedBubble(bubble)
 
+        if (isSynced) {
+            markAsSynced(bubble)
+        }
+
         return getActiveBubble(bubble.id)
     }
 
@@ -136,8 +166,7 @@ class BubbleLocalDataSourceImpl @Inject constructor(
                 deletedAt = Date()
             )
         }
-
-        trashedBubbles.map {
+        trashedBubbles.forEach {
             update(it.toLocal(), tableName)
         }
     }
@@ -148,7 +177,7 @@ class BubbleLocalDataSourceImpl @Inject constructor(
 
     override suspend fun syncBubbles(bubbles: List<BubbleEntity>) {
         if (bubbles.isEmpty()) return
-        
+
         // 배치로 처리하기 위해 모든 관련 버블 ID 수집
         val allBubbleIds = mutableSetOf<String>()
         bubbles.forEach { bubble ->
@@ -156,20 +185,21 @@ class BubbleLocalDataSourceImpl @Inject constructor(
             bubble.backLinks.forEach { allBubbleIds.add(it.id) }
             bubble.linkedBubble?.let { allBubbleIds.add(it.id) }
         }
-        
+
         // 기존 버블들을 배치로 조회
+        val userId = tokenManager.getUserId()
         val existingBubbles = convertLocalBubblesToBubbleEntities(
-            bubbleDao.getActiveBubblesByIds(allBubbleIds.toList())
+            bubbleDao.getActiveBubblesByIds(allBubbleIds.toList(), userId)
         ).associateBy { it.id }
-        
+
         // 각 버블 동기화
         bubbles.forEach { bubble ->
             syncBubbleWithExistingData(bubble, existingBubbles)
         }
     }
-    
+
     private suspend fun syncBubbleWithExistingData(
-        bubble: BubbleEntity, 
+        bubble: BubbleEntity,
         existingBubbles: Map<String, BubbleEntity>
     ) {
         // backLinks 처리
@@ -179,7 +209,7 @@ class BubbleLocalDataSourceImpl @Inject constructor(
                 if (existingBackLink.same(backLink) && existingBackLink.updatedAt > backLink.updatedAt) continue
                 updateBubble(backLink, true)
             } else {
-                addBubble(backLink)
+                addBubble(backLink, null)
             }
             markAsSynced(backLink)
         }
@@ -189,10 +219,10 @@ class BubbleLocalDataSourceImpl @Inject constructor(
             val existingLinkedBubble = existingBubbles[linkedBubble.id]
             if (existingLinkedBubble != null) {
                 if (!existingLinkedBubble.same(linkedBubble)) {
-                    updateBubble(linkedBubble)
+                    updateBubble(linkedBubble, true)
                 }
             } else {
-                addBubble(linkedBubble)
+                addBubble(linkedBubble, null)
             }
             markAsSynced(linkedBubble)
         }
@@ -201,15 +231,15 @@ class BubbleLocalDataSourceImpl @Inject constructor(
         val existingBubble = existingBubbles[bubble.id]
         if (existingBubble != null) {
             if (!existingBubble.same(bubble)) {
-                updateBubble(bubble)
+                updateBubble(bubble, true)
             }
         } else {
-            addBubble(bubble)
+            addBubble(bubble, null)
         }
         markAsSynced(bubble)
     }
 
-    // DELETE
+    // --- DELETE ---
     override suspend fun deleteBubbles(bubbles: List<BubbleEntity>) {
         bubbleDao.deleteBubbles(bubbles.map { it.id })
     }
@@ -217,21 +247,21 @@ class BubbleLocalDataSourceImpl @Inject constructor(
     // Helper function
     private suspend fun addBubbleLabel(bubble: BubbleEntity) {
         if (bubble.labels.isEmpty()) return
-        
+
         val labelIds = bubble.labels.map { it.id }
         val existingLabels = labelDao.getLabelsByIds(labelIds)
         val existingLabelIds = existingLabels.map { it.uuid }.toSet()
-        
+
         // 존재하지 않는 라벨들을 배치로 삽입
         val newLabels = bubble.labels.filter { it.id !in existingLabelIds }
         newLabels.forEach { label ->
             labelDao.insert(label.toLocal())
         }
-        
+
         // 버블-라벨 관계 확인 및 삽입
         val existingRelations = bubbleLabelDao.getBubbleLabelsByIds(listOf(bubble.id), labelIds)
         val existingRelationPairs = existingRelations.map { "${it.bubbleId}-${it.labelId}" }.toSet()
-        
+
         bubble.labels.forEach { label ->
             val relationKey = "${bubble.id}-${label.id}"
             if (relationKey !in existingRelationPairs) {
@@ -247,12 +277,13 @@ class BubbleLocalDataSourceImpl @Inject constructor(
             if (id == null) linkedBubbleDao.insert(bubble.id, linkedBubble.id, false)
         }
 
-        // BackLinks 배치 처리
+        // BackLinks 처리
         if (bubble.backLinks.isNotEmpty()) {
             val backLinkIds = bubble.backLinks.map { it.id }
-            val existingBubbles = bubbleDao.getActiveBubblesByIds(backLinkIds)
+            val userId = tokenManager.getUserId()
+            val existingBubbles = bubbleDao.getActiveBubblesByIds(backLinkIds, userId)
             val existingBubbleIds = existingBubbles.map { it.uuid }.toSet()
-            
+
             bubble.backLinks.forEach { backLink ->
                 if (backLink.id in existingBubbleIds) {
                     val id = linkedBubbleDao.getLinkedBubbleId(bubble.id, backLink.id, true)
@@ -264,24 +295,24 @@ class BubbleLocalDataSourceImpl @Inject constructor(
 
     private suspend fun convertLocalBubblesToBubbleEntities(localBubbles: List<BubbleLocal>): List<BubbleEntity> {
         if (localBubbles.isEmpty()) return emptyList()
-        
+
         val bubbleIds = localBubbles.map { it.uuid }
-        
+
         // 배치로 모든 관련 데이터를 한 번에 조회
         val labelsWithBubbleId = labelDao.getAllActiveLabelsByBubbleIds(bubbleIds)
         val linkedBubblesWithParentId = linkedBubbleDao.getActiveLinkedBubblesByBubbleIds(bubbleIds)
         val backLinksWithParentId = linkedBubbleDao.getActiveBackLinksByBubbleIds(bubbleIds)
-        
+
         // 버블 ID별로 그룹화
         val labelsByBubbleId = labelsWithBubbleId.groupBy { it.bubbleId }
         val linkedBubblesByBubbleId = linkedBubblesWithParentId.groupBy { it.parentBubbleId }
         val backLinksByBubbleId = backLinksWithParentId.groupBy { it.parentBubbleId }
-        
+
         // 각 버블에 대해 관련 데이터를 조합하여 BubbleEntity 생성
         return localBubbles.map { localBubble ->
             val bubbleId = localBubble.uuid
             val baseEntity = localBubble.toData()
-            
+
             baseEntity.copy(
                 labels = labelsByBubbleId[bubbleId]?.map { it.toLabelEntity() } ?: emptyList(),
                 linkedBubble = linkedBubblesByBubbleId[bubbleId]?.firstOrNull()?.toBubbleEntity(),
@@ -289,4 +320,4 @@ class BubbleLocalDataSourceImpl @Inject constructor(
             )
         }
     }
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/umc/edison/local/model/BubbleLocal.kt b/app/src/main/java/com/umc/edison/local/model/BubbleLocal.kt
index 74eba36ba..a25a45757 100644
--- a/app/src/main/java/com/umc/edison/local/model/BubbleLocal.kt
+++ b/app/src/main/java/com/umc/edison/local/model/BubbleLocal.kt
@@ -11,6 +11,7 @@ import java.util.UUID
 data class BubbleLocal(
     @PrimaryKey
     @ColumnInfo(name = "id") override val uuid: String = UUID.randomUUID().toString(),
+    @ColumnInfo(name = "user_id") val userId: String? = null,
     val title: String?,
     val content: String?,
     @ColumnInfo(name = "main_image") val mainImage: String?,
diff --git a/app/src/main/java/com/umc/edison/local/room/dao/BubbleDao.kt b/app/src/main/java/com/umc/edison/local/room/dao/BubbleDao.kt
index 5fcccb8c7..2b66517ac 100644
--- a/app/src/main/java/com/umc/edison/local/room/dao/BubbleDao.kt
+++ b/app/src/main/java/com/umc/edison/local/room/dao/BubbleDao.kt
@@ -7,27 +7,57 @@ import com.umc.edison.local.room.RoomConstant
 
 @Dao
 interface BubbleDao : BaseSyncDao<BubbleLocal> {
-    // READ
-    @Query("SELECT * FROM ${RoomConstant.Table.BUBBLE} WHERE is_deleted = 0 AND is_trashed = 0")
-    suspend fun getAllActiveBubbles(): List<BubbleLocal>
 
-    @Query("SELECT * FROM ${RoomConstant.Table.BUBBLE} WHERE is_deleted = 0 AND is_trashed = 0 AND created_at >= :dayBefore")
-    suspend fun getAllRecentBubbles(dayBefore: Long): List<BubbleLocal>
+    // user_id가 NULL인 버블들을 현재 로그인한 user_id로 일괄 업데이트
+    @Query("UPDATE ${RoomConstant.Table.BUBBLE} SET user_id = :newUserId WHERE user_id IS NULL")
+    suspend fun linkGuestBubblesToUser(newUserId: String)
 
-    @Query("SELECT * FROM ${RoomConstant.Table.BUBBLE} WHERE is_trashed = 1 AND is_deleted = 0")
-    suspend fun getAllTrashedBubbles(): List<BubbleLocal>
+    // 현재 로그인한 사용자의 버블만 조회
+    @Query("""
+        SELECT * FROM ${RoomConstant.Table.BUBBLE} 
+        WHERE is_deleted = 0 AND is_trashed = 0
+        AND ((:userId IS NULL AND user_id IS NULL) OR (user_id = :userId))
+    """)
+    suspend fun getAllActiveBubbles(userId: String?): List<BubbleLocal>
 
-    @Query("SELECT * FROM ${RoomConstant.Table.BUBBLE} WHERE id = :bubbleId AND is_deleted = 0 AND is_trashed = 0")
-    suspend fun getActiveBubbleById(bubbleId: String): BubbleLocal?
+    @Query("""
+        SELECT * FROM ${RoomConstant.Table.BUBBLE} 
+        WHERE is_deleted = 0 AND is_trashed = 0 
+        AND created_at >= :dayBefore
+        AND ((:userId IS NULL AND user_id IS NULL) OR (user_id = :userId))
+    """)
+    suspend fun getAllRecentBubbles(dayBefore: Long, userId: String?): List<BubbleLocal>
 
-    @Query("SELECT * FROM ${RoomConstant.Table.BUBBLE} WHERE id = :bubbleId")
-    suspend fun getRawBubbleById(bubbleId: String): BubbleLocal?
+    @Query("""
+        SELECT * FROM ${RoomConstant.Table.BUBBLE} 
+        WHERE is_trashed = 1 AND is_deleted = 0
+        AND ((:userId IS NULL AND user_id IS NULL) OR (user_id = :userId))
+    """)
+    suspend fun getAllTrashedBubbles(userId: String?): List<BubbleLocal>
 
-    @Query("SELECT * FROM ${RoomConstant.Table.BUBBLE} WHERE id IN (SELECT bubble_id FROM ${RoomConstant.Table.BUBBLE_LABEL} WHERE label_id = :labelId) AND is_deleted = 0 AND is_trashed = 0")
-    suspend fun getBubblesByLabelId(labelId: String): List<BubbleLocal>
+    @Query("""
+        SELECT * FROM ${RoomConstant.Table.BUBBLE} 
+        WHERE id = :bubbleId AND is_deleted = 0 AND is_trashed = 0
+        AND ((:userId IS NULL AND user_id IS NULL) OR (user_id = :userId))
+    """)
+    suspend fun getActiveBubbleById(bubbleId: String, userId: String?): BubbleLocal?
 
-    @Query(
-        """
+    @Query("""
+        SELECT * FROM ${RoomConstant.Table.BUBBLE} 
+        WHERE id = :bubbleId
+        AND ((:userId IS NULL AND user_id IS NULL) OR (user_id = :userId))
+    """)
+    suspend fun getRawBubbleById(bubbleId: String, userId: String?): BubbleLocal?
+
+    @Query("""
+        SELECT * FROM ${RoomConstant.Table.BUBBLE} 
+        WHERE id IN (SELECT bubble_id FROM ${RoomConstant.Table.BUBBLE_LABEL} WHERE label_id = :labelId) 
+        AND is_deleted = 0 AND is_trashed = 0
+        AND ((:userId IS NULL AND user_id IS NULL) OR (user_id = :userId))
+    """)
+    suspend fun getBubblesByLabelId(labelId: String, userId: String?): List<BubbleLocal>
+
+    @Query("""
         SELECT DISTINCT b.* FROM ${RoomConstant.Table.BUBBLE} b
         LEFT JOIN ${RoomConstant.Table.BUBBLE_LABEL} bl ON b.id = bl.bubble_id
         LEFT JOIN ${RoomConstant.Table.LABEL} l ON bl.label_id = l.id
@@ -37,17 +67,25 @@ interface BubbleDao : BaseSyncDao<BubbleLocal> {
             OR l.name LIKE '%' || :query || '%')
             AND b.is_deleted = 0 
             AND b.is_trashed = 0
-        """
-    )
-    suspend fun getSearchBubbles(query: String): List<BubbleLocal>
+            AND ((:userId IS NULL AND b.user_id IS NULL) OR (b.user_id = :userId))
+    """)
+    suspend fun getSearchBubbles(query: String, userId: String?): List<BubbleLocal>
 
-    @Query("SELECT * FROM ${RoomConstant.Table.BUBBLE} WHERE id NOT IN (SELECT bubble_id FROM ${RoomConstant.Table.BUBBLE_LABEL}) AND is_deleted = 0 AND is_trashed = 0")
-    suspend fun getBubblesWithoutLabel(): List<BubbleLocal>
+    @Query("""
+        SELECT * FROM ${RoomConstant.Table.BUBBLE} 
+        WHERE id NOT IN (SELECT bubble_id FROM ${RoomConstant.Table.BUBBLE_LABEL}) 
+        AND is_deleted = 0 AND is_trashed = 0
+        AND ((:userId IS NULL AND user_id IS NULL) OR (user_id = :userId))
+    """)
+    suspend fun getBubblesWithoutLabel(userId: String?): List<BubbleLocal>
 
-    @Query("SELECT * FROM ${RoomConstant.Table.BUBBLE} WHERE id IN (:bubbleIds) AND is_deleted = 0 AND is_trashed = 0")
-    suspend fun getActiveBubblesByIds(bubbleIds: List<String>): List<BubbleLocal>
+    @Query("""
+        SELECT * FROM ${RoomConstant.Table.BUBBLE} 
+        WHERE id IN (:bubbleIds) AND is_deleted = 0 AND is_trashed = 0
+        AND ((:userId IS NULL AND user_id IS NULL) OR (user_id = :userId))
+    """)
+    suspend fun getActiveBubblesByIds(bubbleIds: List<String>, userId: String?): List<BubbleLocal>
 
-    // DELETE
     @Query("DELETE FROM ${RoomConstant.Table.BUBBLE} WHERE id IN (:ids)")
     suspend fun deleteBubbles(ids: List<String>)