diff --git a/connections/implementation/flags/nearby_connections_feature_flags.h b/connections/implementation/flags/nearby_connections_feature_flags.h
index e1b35d9e..73af1c2e 100644
--- a/connections/implementation/flags/nearby_connections_feature_flags.h
+++ b/connections/implementation/flags/nearby_connections_feature_flags.h
@@ -83,6 +83,9 @@ constexpr auto kSafeToDisconnectVersion =
 // When true, use stable endpoint ID.
 constexpr auto kUseStableEndpointId =
     flags::Flag<bool>(kConfigPackage, "45639298", false);
+// When true, disable instant on lost on BLE without extended feature.
+constexpr auto kDisableInstantOnLostOnBleWithoutExtended =
+    flags::Flag<bool>(kConfigPackage, "45687098", false);
 
 }  // namespace nearby_connections_feature
 }  // namespace config_package_nearby
diff --git a/connections/implementation/mediums/ble_v2/instant_on_lost_manager.cc b/connections/implementation/mediums/ble_v2/instant_on_lost_manager.cc
index 44672eeb..4f9978eb 100644
--- a/connections/implementation/mediums/ble_v2/instant_on_lost_manager.cc
+++ b/connections/implementation/mediums/ble_v2/instant_on_lost_manager.cc
@@ -24,8 +24,10 @@
 #include "absl/strings/string_view.h"
 #include "absl/time/clock.h"
 #include "absl/time/time.h"
+#include "connections/implementation/flags/nearby_connections_feature_flags.h"
 #include "connections/implementation/mediums/ble_v2/ble_utils.h"
 #include "connections/implementation/mediums/ble_v2/instant_on_lost_advertisement.h"
+#include "internal/flags/nearby_flags.h"
 #include "internal/platform/ble_v2.h"
 #include "internal/platform/byte_array.h"
 #include "internal/platform/cancelable_alarm.h"
@@ -205,6 +207,16 @@ bool InstantOnLostManager::StartInstantOnLostAdvertisement() {
 
   StopOnLostAdvertising();
 
+  if (NearbyFlags::GetInstance().GetBoolFlag(
+          config_package_nearby::nearby_connections_feature::
+              kDisableInstantOnLostOnBleWithoutExtended) &&
+      !ble_medium_.IsExtendedAdvertisementsAvailable()) {
+    LOG(WARNING)
+        << __func__
+        << ":  Disabling instant on lost on BLE without extended advertising.";
+    return false;
+  }
+
   if (!ble_medium_.StartAdvertising(advertisement_data, advertise_parameters)) {
     LOG(ERROR) << __func__
                << ": Failed to start advertising for instant on lost.";