diff --git a/library/ui-strings/src/main/res/values/strings_sc.xml b/library/ui-strings/src/main/res/values/strings_sc.xml
index cfc39ee8b6..4362b07c01 100644
--- a/library/ui-strings/src/main/res/values/strings_sc.xml
+++ b/library/ui-strings/src/main/res/values/strings_sc.xml
@@ -229,4 +229,9 @@
 
     <string name="action_send_as_sticker">Send as sticker</string>
 
+    <!-- SC-TMP, until merged upstream: https://github.com/vector-im/element-android/pull/5781 -->
+    <string name="settings_call_ringtone_use_default_stun_title">Allow fallback call assist server</string>
+    <string name="settings_call_ringtone_use_default_stun_summary">Will use %s as assist when your homeserver does not offer one (your IP address will be seen by the stun server during a call
+)</string>
+
 </resources>
diff --git a/vector-config/src/main/res/values/config.xml b/vector-config/src/main/res/values/config.xml
index 810aab2273..f231ca5ab8 100755
--- a/vector-config/src/main/res/values/config.xml
+++ b/vector-config/src/main/res/values/config.xml
@@ -5,6 +5,7 @@
 
     <!-- server urls -->
     <string name="matrix_org_server_url" translatable="false">https://matrix.org</string>
+    <string name="fallback_stun_server_url" translatable="false">turn.matrix.org</string>
 
     <!-- Rageshake configuration -->
     <string name="bug_report_url" translatable="false">https://rageshake.schildi.chat/api/submit</string>
diff --git a/vector/src/main/java/im/vector/app/features/call/webrtc/WebRtcCall.kt b/vector/src/main/java/im/vector/app/features/call/webrtc/WebRtcCall.kt
index 9c65d94a94..31b29e4bd4 100644
--- a/vector/src/main/java/im/vector/app/features/call/webrtc/WebRtcCall.kt
+++ b/vector/src/main/java/im/vector/app/features/call/webrtc/WebRtcCall.kt
@@ -19,6 +19,8 @@ package im.vector.app.features.call.webrtc
 import android.content.Context
 import android.hardware.camera2.CameraManager
 import androidx.core.content.getSystemService
+import im.vector.app.R
+import im.vector.app.core.resources.StringProvider
 import im.vector.app.core.services.CallAndroidService
 import im.vector.app.core.utils.PublishDataSource
 import im.vector.app.core.utils.TextUtils.formatDuration
@@ -35,6 +37,7 @@ import im.vector.app.features.call.utils.awaitSetLocalDescription
 import im.vector.app.features.call.utils.awaitSetRemoteDescription
 import im.vector.app.features.call.utils.mapToCallCandidate
 import im.vector.app.features.session.coroutineScope
+import im.vector.app.features.settings.VectorPreferences
 import im.vector.lib.core.utils.flow.chunk
 import im.vector.lib.core.utils.timer.CountUpTimer
 import kotlinx.coroutines.CoroutineScope
@@ -114,7 +117,9 @@ class WebRtcCall(
         private val sessionProvider: Provider<Session?>,
         private val peerConnectionFactoryProvider: Provider<PeerConnectionFactory?>,
         private val onCallBecomeActive: (WebRtcCall) -> Unit,
-        private val onCallEnded: (String, EndCallReason, Boolean) -> Unit
+        private val onCallEnded: (String, EndCallReason, Boolean) -> Unit,
+        private var vectorPreferences: VectorPreferences,
+        private val stringProvider: StringProvider
 ) : MxCall.StateListener {
 
     interface Listener : MxCall.StateListener {
@@ -299,6 +304,14 @@ class WebRtcCall(
                     )
                 }
             }
+            if ((turnServerResponse == null || turnServerResponse.uris.isNullOrEmpty()) && vectorPreferences.useFallbackTurnServer()) {
+                add(
+                        PeerConnection
+                                .IceServer
+                                .builder("stun:" + stringProvider.getString(R.string.fallback_stun_server_url))
+                                .createIceServer()
+                )
+            }
         }
         Timber.tag(loggerTag.value).v("creating peer connection...with iceServers $iceServers ")
         val rtcConfig = PeerConnection.RTCConfiguration(iceServers).apply {
diff --git a/vector/src/main/java/im/vector/app/features/call/webrtc/WebRtcCallManager.kt b/vector/src/main/java/im/vector/app/features/call/webrtc/WebRtcCallManager.kt
index f229f30e7b..522a771808 100644
--- a/vector/src/main/java/im/vector/app/features/call/webrtc/WebRtcCallManager.kt
+++ b/vector/src/main/java/im/vector/app/features/call/webrtc/WebRtcCallManager.kt
@@ -21,6 +21,7 @@ import androidx.lifecycle.DefaultLifecycleObserver
 import androidx.lifecycle.LifecycleOwner
 import im.vector.app.ActiveSessionDataSource
 import im.vector.app.core.pushers.UnifiedPushHelper
+import im.vector.app.core.resources.StringProvider
 import im.vector.app.core.services.CallAndroidService
 import im.vector.app.features.analytics.AnalyticsTracker
 import im.vector.app.features.analytics.plan.CallEnded
@@ -32,6 +33,7 @@ import im.vector.app.features.call.lookup.CallUserMapper
 import im.vector.app.features.call.utils.EglUtils
 import im.vector.app.features.call.vectorCallService
 import im.vector.app.features.session.coroutineScope
+import im.vector.app.features.settings.VectorPreferences
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.asCoroutineDispatcher
 import org.matrix.android.sdk.api.extensions.orFalse
@@ -74,6 +76,8 @@ class WebRtcCallManager @Inject constructor(
         private val analyticsTracker: AnalyticsTracker,
         private val unifiedPushHelper: UnifiedPushHelper,
         private val voipConfig: VoipConfig,
+        private var vectorPreferences: VectorPreferences,
+        private val stringProvider: StringProvider,
 ) : CallListener,
         DefaultLifecycleObserver {
 
@@ -336,7 +340,9 @@ class WebRtcCallManager @Inject constructor(
                 },
                 sessionProvider = { currentSession },
                 onCallBecomeActive = this::onCallActive,
-                onCallEnded = this::onCallEnded
+                onCallEnded = this::onCallEnded,
+                vectorPreferences = vectorPreferences,
+                stringProvider = stringProvider
         )
         advertisedCalls.add(mxCall.callId)
         callsByCallId[mxCall.callId] = webRtcCall
diff --git a/vector/src/main/java/im/vector/app/features/settings/VectorPreferences.kt b/vector/src/main/java/im/vector/app/features/settings/VectorPreferences.kt
index 072f15190e..6ad1b65006 100755
--- a/vector/src/main/java/im/vector/app/features/settings/VectorPreferences.kt
+++ b/vector/src/main/java/im/vector/app/features/settings/VectorPreferences.kt
@@ -176,6 +176,7 @@ class VectorPreferences @Inject constructor(
 
         // Calls
         const val SETTINGS_CALL_PREVENT_ACCIDENTAL_CALL_KEY = "SETTINGS_CALL_PREVENT_ACCIDENTAL_CALL_KEY"
+        const val SETTINGS_CALL_USE_FALLBACK_CALL_ASSIST_SERVER_KEY = "SETTINGS_CALL_USE_FALLBACK_CALL_ASSIST_SERVER_KEY"
         const val SETTINGS_CALL_RINGTONE_USE_RIOT_PREFERENCE_KEY = "SETTINGS_CALL_RINGTONE_USE_RIOT_PREFERENCE_KEY"
         const val SETTINGS_CALL_RINGTONE_URI_PREFERENCE_KEY = "SETTINGS_CALL_RINGTONE_URI_PREFERENCE_KEY"
 
@@ -859,6 +860,13 @@ class VectorPreferences @Inject constructor(
         return defaultPrefs.getBoolean(SETTINGS_CALL_PREVENT_ACCIDENTAL_CALL_KEY, true)
     }
 
+    /**
+     * Tells if turn.matrix should be used during calls as a fallback
+     */
+    fun useFallbackTurnServer(): Boolean {
+        return defaultPrefs.getBoolean(SETTINGS_CALL_USE_FALLBACK_CALL_ASSIST_SERVER_KEY, false)
+    }
+
     /**
      * Tells if the read receipts should be shown.
      *
diff --git a/vector/src/main/java/im/vector/app/features/settings/VectorSettingsVoiceVideoFragment.kt b/vector/src/main/java/im/vector/app/features/settings/VectorSettingsVoiceVideoFragment.kt
index 1cb7dcbf28..16752e10a5 100644
--- a/vector/src/main/java/im/vector/app/features/settings/VectorSettingsVoiceVideoFragment.kt
+++ b/vector/src/main/java/im/vector/app/features/settings/VectorSettingsVoiceVideoFragment.kt
@@ -46,6 +46,9 @@ class VectorSettingsVoiceVideoFragment : VectorSettingsBaseFragment() {
     private val mCallRingtonePreference by lazy {
         findPreference<VectorPreference>(VectorPreferences.SETTINGS_CALL_RINGTONE_URI_PREFERENCE_KEY)!!
     }
+    private val useDefaultStunPreference by lazy {
+        findPreference<SwitchPreference>(VectorPreferences.SETTINGS_CALL_USE_FALLBACK_CALL_ASSIST_SERVER_KEY)!!
+    }
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -59,6 +62,11 @@ class VectorSettingsVoiceVideoFragment : VectorSettingsBaseFragment() {
             false
         }
 
+        useDefaultStunPreference.let {
+            val stun = getString(R.string.fallback_stun_server_url)
+            it.summary = getString(R.string.settings_call_ringtone_use_default_stun_summary, stun)
+        }
+
         mCallRingtonePreference.let {
             it.summary = ringtoneUtils.getCallRingtoneName()
             it.onPreferenceClickListener = Preference.OnPreferenceClickListener {
diff --git a/vector/src/main/res/xml/vector_settings_voice_video.xml b/vector/src/main/res/xml/vector_settings_voice_video.xml
index 4ffa8d668a..020406e39e 100644
--- a/vector/src/main/res/xml/vector_settings_voice_video.xml
+++ b/vector/src/main/res/xml/vector_settings_voice_video.xml
@@ -18,6 +18,12 @@
             android:title="@string/settings_hide_call_buttons"
             android:summary="@string/settings_hide_call_buttons_summary" />
 
+        <im.vector.app.core.preference.VectorSwitchPreference
+            android:defaultValue="false"
+            android:key="SETTINGS_CALL_USE_FALLBACK_CALL_ASSIST_SERVER_KEY"
+            android:summary="@string/settings_call_ringtone_use_default_stun_summary"
+            android:title="@string/settings_call_ringtone_use_default_stun_title" />
+
         <im.vector.app.core.preference.VectorSwitchPreference
             android:defaultValue="true"
             android:disableDependentsState="true"
@@ -33,4 +39,4 @@
 
     </im.vector.app.core.preference.VectorPreferenceCategory>
 
-</androidx.preference.PreferenceScreen>
\ No newline at end of file
+</androidx.preference.PreferenceScreen>