diff --git a/Runtime/ServiceLocator.cs b/Runtime/ServiceLocator.cs
index 25c07db..a3cd782 100644
--- a/Runtime/ServiceLocator.cs
+++ b/Runtime/ServiceLocator.cs
@@ -11,6 +11,7 @@ public interface IService { }
 
     public static class ServiceLocator
     {
+        public delegate void ServiceCallback<T>(T service, bool registered);
         private delegate void ServiceLocatorDelegate(IService service, bool registered);
 
         private static readonly Dictionary<Type, IService> k_Services = new();
@@ -55,7 +56,7 @@ public static bool Unregister<T>(T service) where T : class, IService
             return false;
         }
 
-        private static bool TryGetService<T>(out T result) where T : class, IService
+        public static bool TryGetService<T>(out T result) where T : class, IService
         {
             if (k_Services.TryGetValue(typeof(T), out var service))
             {
@@ -67,7 +68,7 @@ private static bool TryGetService<T>(out T result) where T : class, IService
             return false;
         }
 
-        public static void AddServiceListener<T>(Action<T, bool> serviceCallback) where T : class, IService
+        public static void AddServiceListener<T>(ServiceCallback<T> serviceCallback) where T : class, IService
         {
             if (k_RegisteredCallbacks.ContainsKey(serviceCallback))
             {
@@ -75,6 +76,7 @@ public static void AddServiceListener<T>(Action<T, bool> serviceCallback) where
                 return;
             }
 
+            // If the service is registered immediately notify the listener
             if (TryGetService<T>(out var service))
             {
                 serviceCallback.Invoke(service, true);
@@ -96,13 +98,20 @@ public static void AddServiceListener<T>(Action<T, bool> serviceCallback) where
             k_RegisteredCallbacks.Add(serviceCallback, callbackWrapper);
         }
 
-        public static void RemoveServiceListener<T>(Action<T, bool> serviceCallback) where T : class, IService
+        public static void RemoveServiceListener<T>(ServiceCallback<T> serviceCallback) where T : class, IService
         {
             if (!k_RegisteredCallbacks.TryGetValue(serviceCallback, out var callbackWrapper))
             {
                 return;
             }
 
+            // If the service is registered immediately notify the listener
+            if (TryGetService<T>(out var service))
+            {
+                // behave as if the service unregistered.
+                callbackWrapper.Invoke(service, false);
+            }
+
             var type = typeof(T);
 
             if (k_Callbacks.ContainsKey(type))