diff --git a/src/core/border_router/routing_manager.cpp b/src/core/border_router/routing_manager.cpp
index 80aeac3fa..3b1a75582 100644
--- a/src/core/border_router/routing_manager.cpp
+++ b/src/core/border_router/routing_manager.cpp
@@ -2122,6 +2122,7 @@ void RoutingManager::OnLinkPrefixManager::GenerateLocalPrefix(void)
 {
     const MeshCoP::ExtendedPanId &extPanId = Get<MeshCoP::ExtendedPanIdManager>().GetExtPanId();
     OldPrefix *                   entry;
+    Ip6::Prefix                   oldLocalPrefix = mLocalPrefix;
 
     // Global ID: 40 most significant bits of Extended PAN ID
     // Subnet ID: 16 least significant bits of Extended PAN ID
@@ -2132,6 +2133,11 @@ void RoutingManager::OnLinkPrefixManager::GenerateLocalPrefix(void)
 
     mLocalPrefix.SetLength(kOnLinkPrefixLength);
 
+    // We ensure that the local prefix did change, since not all the
+    // bytes in Extended PAN ID are used in derivation of the local prefix.
+
+    VerifyOrExit(mLocalPrefix != oldLocalPrefix);
+
     LogNote("Local on-link prefix: %s", mLocalPrefix.ToString().AsCString());
 
     // Check if the new local prefix happens to be in `mOldLocalPrefixes` array.
@@ -2149,6 +2155,9 @@ void RoutingManager::OnLinkPrefixManager::GenerateLocalPrefix(void)
     {
         mState = kIdle;
     }
+
+exit:
+    return;
 }
 
 void RoutingManager::OnLinkPrefixManager::Start(void)
@@ -2462,6 +2471,8 @@ void RoutingManager::OnLinkPrefixManager::HandleExtPanIdChange(void)
 
     GenerateLocalPrefix();
 
+    VerifyOrExit(oldPrefix != mLocalPrefix);
+
     switch (oldState)
     {
     case kIdle:
@@ -2481,6 +2492,9 @@ void RoutingManager::OnLinkPrefixManager::HandleExtPanIdChange(void)
     {
         Get<RoutingManager>().ScheduleRoutingPolicyEvaluation(kAfterRandomDelay);
     }
+
+exit:
+    return;
 }
 
 void RoutingManager::OnLinkPrefixManager::DeprecateOldPrefix(const Ip6::Prefix &aPrefix, TimeMilli aExpireTime)
diff --git a/tests/unit/test_routing_manager.cpp b/tests/unit/test_routing_manager.cpp
index cf0a24124..76672fc2b 100644
--- a/tests/unit/test_routing_manager.cpp
+++ b/tests/unit/test_routing_manager.cpp
@@ -829,7 +829,7 @@ void VerifyPrefixTable(const OnLinkPrefix *aOnLinkPrefixes,
     VerifyOrQuit(routePrefixCount == aNumRoutePrefixes);
 }
 
-void InitTest(void)
+void InitTest(bool aEnablBorderRouting = false)
 {
     //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     // Initialize OT instance.
@@ -843,13 +843,14 @@ void InitTest(void)
     SuccessOrQuit(sInfraIfAddress.FromString(kInfraIfAddress));
 
     //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-    // Initialize Border Router and start Thread operation.
+    // Initialize and start Border Router and Thread operation.
 
     SuccessOrQuit(otBorderRoutingInit(sInstance, kInfraIfIndex, /* aInfraIfIsRunning */ true));
 
     SuccessOrQuit(otLinkSetPanId(sInstance, 0x1234));
     SuccessOrQuit(otIp6SetEnabled(sInstance, true));
     SuccessOrQuit(otThreadSetEnabled(sInstance, true));
+    SuccessOrQuit(otBorderRoutingSetEnabled(sInstance, aEnablBorderRouting));
 
     //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     // Ensure device starts as leader.
@@ -2514,18 +2515,16 @@ void TestSavedOnLinkPrefixes(void)
     Log("--------------------------------------------------------------------------------------------");
     Log("TestSavedOnLinkPrefixes");
 
-    InitTest();
+    InitTest(/* aEnablBorderRouting */ true);
 
     //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-    // Start Routing Manager. Check emitted RS and RA messages.
+    // Check emitted RS and RA messages.
 
     sRsEmitted   = false;
     sRaValidated = false;
     sExpectedPio = kPioAdvertisingLocalOnLink;
     sExpectedRios.Clear();
 
-    SuccessOrQuit(sInstance->Get<BorderRouter::RoutingManager>().SetEnabled(true));
-
     SuccessOrQuit(sInstance->Get<BorderRouter::RoutingManager>().GetOnLinkPrefix(localOnLink));
     SuccessOrQuit(sInstance->Get<BorderRouter::RoutingManager>().GetOmrPrefix(localOmr));
 
@@ -2553,10 +2552,7 @@ void TestSavedOnLinkPrefixes(void)
 
     testFreeInstance(sInstance);
 
-    InitTest();
-
-    //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-    // Start Routing Manager.
+    InitTest(/* aEnablBorderRouting */ true);
 
     SuccessOrQuit(sInstance->Get<BorderRouter::RoutingManager>().SetEnabled(true));
 
@@ -2594,12 +2590,7 @@ void TestSavedOnLinkPrefixes(void)
 
     testFreeInstance(sInstance);
 
-    InitTest();
-
-    //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-    // Start Routing Manager.
-
-    SuccessOrQuit(sInstance->Get<BorderRouter::RoutingManager>().SetEnabled(true));
+    InitTest(/* aEnablBorderRouting */ true);
 
     sExpectedPio = kPioAdvertisingLocalOnLink;