diff --git a/libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/spaces/SpaceRoom.kt b/libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/spaces/SpaceRoom.kt
index b14d688f02..3e72632e6c 100644
--- a/libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/spaces/SpaceRoom.kt
+++ b/libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/spaces/SpaceRoom.kt
@@ -7,15 +7,14 @@
 
 package io.element.android.libraries.matrix.api.spaces
 
-import androidx.compose.runtime.Immutable
 import io.element.android.libraries.matrix.api.core.RoomAlias
 import io.element.android.libraries.matrix.api.core.RoomId
 import io.element.android.libraries.matrix.api.room.CurrentUserMembership
 import io.element.android.libraries.matrix.api.room.RoomType
 import io.element.android.libraries.matrix.api.room.join.JoinRule
 import io.element.android.libraries.matrix.api.user.MatrixUser
+import kotlinx.collections.immutable.ImmutableList
 
-@Immutable
 data class SpaceRoom(
     val rawName: String?,
     val displayName: String,
@@ -23,7 +22,7 @@ data class SpaceRoom(
     val canonicalAlias: RoomAlias?,
     val childrenCount: Int,
     val guestCanJoin: Boolean,
-    val heroes: List<MatrixUser>,
+    val heroes: ImmutableList<MatrixUser>,
     val joinRule: JoinRule?,
     val numJoinedMembers: Int,
     val roomId: RoomId,
@@ -34,7 +33,7 @@ data class SpaceRoom(
     /**
      * The via parameters of the room.
      */
-    val via: List<String>,
+    val via: ImmutableList<String>,
     val isDirect: Boolean?,
 ) {
     val isSpace = roomType == RoomType.Space
diff --git a/libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/spaces/SpaceRoomMapper.kt b/libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/spaces/SpaceRoomMapper.kt
index ac5cbf5c00..3a9b78c3f9 100644
--- a/libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/spaces/SpaceRoomMapper.kt
+++ b/libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/spaces/SpaceRoomMapper.kt
@@ -13,6 +13,7 @@ import io.element.android.libraries.matrix.api.core.RoomId
 import io.element.android.libraries.matrix.api.spaces.SpaceRoom
 import io.element.android.libraries.matrix.impl.room.join.map
 import io.element.android.libraries.matrix.impl.room.map
+import kotlinx.collections.immutable.toImmutableList
 import org.matrix.rustcomponents.sdk.SpaceRoom as RustSpaceRoom
 
 class SpaceRoomMapper {
@@ -22,7 +23,7 @@ class SpaceRoomMapper {
             canonicalAlias = spaceRoom.canonicalAlias?.let(::RoomAlias),
             childrenCount = spaceRoom.childrenCount.toInt(),
             guestCanJoin = spaceRoom.guestCanJoin,
-            heroes = spaceRoom.heroes.orEmpty().map { it.map() },
+            heroes = spaceRoom.heroes.orEmpty().map { it.map() }.toImmutableList(),
             joinRule = spaceRoom.joinRule?.map(),
             rawName = spaceRoom.rawName,
             displayName = spaceRoom.displayName,
@@ -32,7 +33,7 @@ class SpaceRoomMapper {
             state = spaceRoom.state?.map(),
             topic = spaceRoom.topic,
             worldReadable = spaceRoom.worldReadable.orFalse(),
-            via = spaceRoom.via,
+            via = spaceRoom.via.toImmutableList(),
             isDirect = spaceRoom.isDirect,
         )
     }
diff --git a/libraries/previewutils/src/main/kotlin/io/element/android/libraries/previewutils/room/SpaceRoomFixture.kt b/libraries/previewutils/src/main/kotlin/io/element/android/libraries/previewutils/room/SpaceRoomFixture.kt
index 5f8fd2ee38..aae6bbfb76 100644
--- a/libraries/previewutils/src/main/kotlin/io/element/android/libraries/previewutils/room/SpaceRoomFixture.kt
+++ b/libraries/previewutils/src/main/kotlin/io/element/android/libraries/previewutils/room/SpaceRoomFixture.kt
@@ -14,6 +14,7 @@ import io.element.android.libraries.matrix.api.room.RoomType
 import io.element.android.libraries.matrix.api.room.join.JoinRule
 import io.element.android.libraries.matrix.api.spaces.SpaceRoom
 import io.element.android.libraries.matrix.api.user.MatrixUser
+import kotlinx.collections.immutable.toImmutableList
 
 fun aSpaceRoom(
     rawName: String? = null,
@@ -39,7 +40,7 @@ fun aSpaceRoom(
     canonicalAlias = canonicalAlias,
     childrenCount = childrenCount,
     guestCanJoin = guestCanJoin,
-    heroes = heroes,
+    heroes = heroes.toImmutableList(),
     joinRule = joinRule,
     numJoinedMembers = numJoinedMembers,
     roomId = roomId,
@@ -47,6 +48,6 @@ fun aSpaceRoom(
     state = state,
     topic = topic,
     worldReadable = worldReadable,
-    via = via,
+    via = via.toImmutableList(),
     isDirect = isDirect
 )