diff --git a/api/current.txt b/api/current.txt
index 7e3629274ba6f..bafd4711cca33 100755
--- a/api/current.txt
+++ b/api/current.txt
@@ -42640,6 +42640,7 @@ package android.telephony {
     method public java.util.List<android.telephony.SubscriptionPlan> getSubscriptionPlans(int);
     method public boolean isActiveSubscriptionId(int);
     method public boolean isNetworkRoaming(int);
+    method public static boolean isUsableSubscriptionId(int);
     method public static boolean isValidSubscriptionId(int);
     method public void removeOnOpportunisticSubscriptionsChangedListener(android.telephony.SubscriptionManager.OnOpportunisticSubscriptionsChangedListener);
     method public void removeOnSubscriptionsChangedListener(android.telephony.SubscriptionManager.OnSubscriptionsChangedListener);
@@ -42653,6 +42654,7 @@ package android.telephony {
     field public static final java.lang.String ACTION_REFRESH_SUBSCRIPTION_PLANS = "android.telephony.action.REFRESH_SUBSCRIPTION_PLANS";
     field public static final int DATA_ROAMING_DISABLE = 0; // 0x0
     field public static final int DATA_ROAMING_ENABLE = 1; // 0x1
+    field public static final int DEFAULT_SUBSCRIPTION_ID = 2147483647; // 0x7fffffff
     field public static final java.lang.String EXTRA_SUBSCRIPTION_INDEX = "android.telephony.extra.SUBSCRIPTION_INDEX";
     field public static final int INVALID_SUBSCRIPTION_ID = -1; // 0xffffffff
   }
diff --git a/telephony/java/android/telephony/SubscriptionManager.java b/telephony/java/android/telephony/SubscriptionManager.java
index 3ef80c2efcb51..ad169017552f0 100644
--- a/telephony/java/android/telephony/SubscriptionManager.java
+++ b/telephony/java/android/telephony/SubscriptionManager.java
@@ -89,9 +89,7 @@ public class SubscriptionManager {
     /** @hide */
     public static final int INVALID_SIM_SLOT_INDEX = -1;
 
-    /** Indicates the caller wants the default sub id. */
-    /** @hide */
-    @UnsupportedAppUsage
+    /** Indicates the default subscription ID in Telephony. */
     public static final int DEFAULT_SUBSCRIPTION_ID = Integer.MAX_VALUE;
 
     /**
@@ -1600,6 +1598,19 @@ public class SubscriptionManager {
         return subscriptionId > INVALID_SUBSCRIPTION_ID;
     }
 
+    /**
+     * Check if the subscription ID is usable.
+     *
+     * A usable subscription ID has a valid value except some special values such as
+     * {@link DEFAULT_SUBSCRIPTION_ID}. It can be used for subscription functions.
+     *
+     * @param subscriptionId the subscription ID
+     * @return {@code true} if the subscription ID is usable; {@code false} otherwise.
+     */
+    public static boolean isUsableSubscriptionId(int subscriptionId) {
+        return isUsableSubIdValue(subscriptionId);
+    }
+
     /**
      * @return true if subId is an usable subId value else false. A
      * usable subId means its neither a INVALID_SUBSCRIPTION_ID nor a DEFAULT_SUB_ID.