diff --git a/CHANGES.md b/CHANGES.md
index fd7d92c9..31123b11 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,12 @@
 # Change Log
 
+## ? - ?
+
+##### Additions :tada:
+
+##### Fixes :wrench:
+- Fixed a bug related to using offline tilesets without internet connection.
+  
 ## v1.16.0 - 2025-05-01
 
 ##### Additions :tada:
diff --git a/Editor/CesiumEditorUtility.cs b/Editor/CesiumEditorUtility.cs
index f6edd7fb..78f8eff5 100644
--- a/Editor/CesiumEditorUtility.cs
+++ b/Editor/CesiumEditorUtility.cs
@@ -21,6 +21,8 @@ static CesiumEditorUtility()
 
         static void UpdateIonSession()
         {
+            if (!IsNetworkReachable())
+                return;
             try
             {
                 CesiumIonServerManager.instance.currentSession.Tick();
@@ -34,6 +36,28 @@ static void UpdateIonSession()
             }
         }
 
+        private static bool IsNetworkReachable()
+        {
+            switch (Application.internetReachability)
+            {
+                case NetworkReachability.ReachableViaCarrierDataNetwork:
+                    // Reachable via carrier data network
+                    return true;
+
+                case NetworkReachability.ReachableViaLocalAreaNetwork:
+                    // Reachable via Local Area Network.
+                    return true;
+
+                case NetworkReachability.NotReachable:
+                    // Not Reachable.
+                    return false;
+
+                default:
+                    // Not Reachable.
+                    return false;
+            }
+        }
+
         static void
         HandleCesium3DTilesetLoadFailure(Cesium3DTilesetLoadFailureDetails details)
         {