diff --git a/src/core/border_router/routing_manager.cpp b/src/core/border_router/routing_manager.cpp
index edb808332..496f14da0 100644
--- a/src/core/border_router/routing_manager.cpp
+++ b/src/core/border_router/routing_manager.cpp
@@ -169,7 +169,7 @@ Error RoutingManager::LoadOrGenerateRandomOnLinkPrefix(void)
     Error error = kErrorNone;
 
     if (Get<Settings>().Read<Settings::OnLinkPrefix>(mLocalOnLinkPrefix) != kErrorNone ||
-        !IsValidOnLinkPrefix(mLocalOnLinkPrefix))
+        !mLocalOnLinkPrefix.IsUniqueLocal())
     {
         Ip6::NetworkPrefix randomOnLinkPrefix;
 
@@ -803,9 +803,7 @@ bool RoutingManager::IsValidOnLinkPrefix(const RouterAdv::PrefixInfoOption &aPio
 
 bool RoutingManager::IsValidOnLinkPrefix(const Ip6::Prefix &aOnLinkPrefix)
 {
-    // Accept ULA prefix with length of 64 bits and GUA prefix.
-    return (aOnLinkPrefix.mLength == kOnLinkPrefixLength && aOnLinkPrefix.mPrefix.mFields.m8[0] == 0xfd) ||
-           (aOnLinkPrefix.mLength >= 3 && (aOnLinkPrefix.GetBytes()[0] & 0xE0) == 0x20);
+    return !aOnLinkPrefix.IsLinkLocal() && !aOnLinkPrefix.IsMulticast();
 }
 
 void RoutingManager::HandleRouterAdvertisementTimer(Timer &aTimer)
diff --git a/src/core/net/ip6_address.hpp b/src/core/net/ip6_address.hpp
index ca8055bed..9139af7bd 100644
--- a/src/core/net/ip6_address.hpp
+++ b/src/core/net/ip6_address.hpp
@@ -159,6 +159,36 @@ public:
      */
     bool IsValid(void) const { return (mLength <= kMaxLength); }
 
+    /**
+     * This method indicates whether the prefix is a Link-Local prefix.
+     *
+     * @retval TRUE   The prefix is a Link-Local prefix.
+     * @retval FALSE  The prefix is not a Link-Local prefix.
+     *
+     */
+    bool IsLinkLocal(void) const
+    {
+        return mLength >= 10 && mPrefix.mFields.m8[0] == 0xfe && (mPrefix.mFields.m8[1] & 0xc0) == 0x80;
+    }
+
+    /**
+     * This method indicates whether the prefix is a Multicast prefix.
+     *
+     * @retval TRUE   The prefix is a Multicast prefix.
+     * @retval FALSE  The prefix is not a Multicast prefix.
+     *
+     */
+    bool IsMulticast(void) const { return mLength >= 8 && mPrefix.mFields.m8[0] == 0xff; }
+
+    /**
+     * This method indicates whether the prefix is a Unique-Local prefix.
+     *
+     * @retval TRUE   The prefix is a Unique-Local prefix.
+     * @retval FALSE  The prefix is not a Unique-Local prefix.
+     *
+     */
+    bool IsUniqueLocal(void) const { return mLength >= 7 && (mPrefix.mFields.m8[0] & 0xfe) == 0xfc; }
+
     /**
      * This method indicates whether the prefix is equal to a given prefix.
      *