diff --git a/include/openthread/instance.h b/include/openthread/instance.h
index 9ba8a3b5f..64ee8d644 100644
--- a/include/openthread/instance.h
+++ b/include/openthread/instance.h
@@ -52,7 +52,7 @@ extern "C" {
  *
  * @note This number versions both OpenThread platform and user APIs.
  */
-#define OPENTHREAD_API_VERSION (574)
+#define OPENTHREAD_API_VERSION (575)
 
 /**
  * @addtogroup api-instance
diff --git a/include/openthread/platform/infra_if.h b/include/openthread/platform/infra_if.h
index d46423a36..46751c680 100644
--- a/include/openthread/platform/infra_if.h
+++ b/include/openthread/platform/infra_if.h
@@ -147,8 +147,13 @@ extern otError otPlatInfraIfStateChanged(otInstance *aInstance, uint32_t aInfraI
  *
  * @param[in]  aInfraIfIndex  The index of the infrastructure interface to discover the NAT64 prefix.
  *
- * @retval  OT_ERROR_NONE    Successfully request NAT64 prefix discovery.
- * @retval  OT_ERROR_FAILED  Failed to request NAT64 prefix discovery.
+ * @retval  OT_ERROR_NONE             Successfully requested NAT64 prefix discovery.
+ * @retval  OT_ERROR_FAILED           Failed to request NAT64 prefix discovery.
+ * @retval  OT_ERROR_NOT_IMPLEMENTED  Platform does not support this discovery method. will rely on RA-based mechanism.
+ *
+ * @note  This function requests the platform to discover a NAT64 prefix (e.g. using RFC 7050 DNS-based
+ *        discovery). The priority of the discovered prefix is lower than that of the prefix discovered via Router
+ *        Advertisements PREF64 option (RFC 8781).
  */
 otError otPlatInfraIfDiscoverNat64Prefix(uint32_t aInfraIfIndex);
 
@@ -162,6 +167,10 @@ otError otPlatInfraIfDiscoverNat64Prefix(uint32_t aInfraIfIndex);
  * @param[in]  aInstance      The OpenThread instance structure.
  * @param[in]  aInfraIfIndex  The index of the infrastructure interface on which the NAT64 prefix is discovered.
  * @param[in]  aIp6Prefix     A pointer to NAT64 prefix.
+ *
+ * @note  This function is used to report a NAT64 prefix discovered by the platform (e.g. using RFC 7050 DNS-based
+ *        discovery). The priority of the discovered prefix is lower than that of the prefix discovered via Router
+ *        Advertisements PREF64 option (RFC 8781).
  */
 extern void otPlatInfraIfDiscoverNat64PrefixDone(otInstance        *aInstance,
                                                  uint32_t           aInfraIfIndex,