diff --git a/api/system-current.txt b/api/system-current.txt
index 5fd2bf8db0a99..af902d4d32bbc 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -5397,6 +5397,8 @@ package android.telephony {
   public class SubscriptionManager {
     method public java.util.List<android.telephony.SubscriptionInfo> getAvailableSubscriptionInfoList();
     method public void requestEmbeddedSubscriptionInfoListRefresh();
+    method public void setDefaultDataSubId(int);
+    method public void setDefaultSmsSubId(int);
     field public static final android.net.Uri ADVANCED_CALLING_ENABLED_CONTENT_URI;
     field public static final android.net.Uri VT_ENABLED_CONTENT_URI;
     field public static final android.net.Uri WFC_ENABLED_CONTENT_URI;
diff --git a/telephony/java/android/telephony/SubscriptionManager.java b/telephony/java/android/telephony/SubscriptionManager.java
index b3c4b827516d0..3235507d76cd1 100644
--- a/telephony/java/android/telephony/SubscriptionManager.java
+++ b/telephony/java/android/telephony/SubscriptionManager.java
@@ -1601,14 +1601,23 @@ public class SubscriptionManager {
         return subId;
     }
 
-    /** @hide */
-    @UnsupportedAppUsage
-    public void setDefaultSmsSubId(int subId) {
-        if (VDBG) logd("setDefaultSmsSubId sub id = " + subId);
+    /**
+     * Set the subscription which will be used by default for SMS, with the subscription which
+     * the supplied subscription ID corresponds to; or throw a RuntimeException if the supplied
+     * subscription ID is not usable (check with {@link #isUsableSubscriptionId(int)}).
+     *
+     * @param subscriptionId the supplied subscription ID
+     *
+     * @hide
+     */
+    @SystemApi
+    @RequiresPermission(android.Manifest.permission.MODIFY_PHONE_STATE)
+    public void setDefaultSmsSubId(int subscriptionId) {
+        if (VDBG) logd("setDefaultSmsSubId sub id = " + subscriptionId);
         try {
             ISub iSub = ISub.Stub.asInterface(ServiceManager.getService("isub"));
             if (iSub != null) {
-                iSub.setDefaultSmsSubId(subId);
+                iSub.setDefaultSmsSubId(subscriptionId);
             }
         } catch (RemoteException ex) {
             // ignore it
@@ -1656,14 +1665,23 @@ public class SubscriptionManager {
         return subId;
     }
 
-    /** @hide */
-    @UnsupportedAppUsage
-    public void setDefaultDataSubId(int subId) {
-        if (VDBG) logd("setDataSubscription sub id = " + subId);
+    /**
+     * Set the subscription which will be used by default for data, with the subscription which
+     * the supplied subscription ID corresponds to; or throw a RuntimeException if the supplied
+     * subscription ID is not usable (check with {@link #isUsableSubscriptionId(int)}).
+     *
+     * @param subscriptionId the supplied subscription ID
+     *
+     * @hide
+     */
+    @SystemApi
+    @RequiresPermission(android.Manifest.permission.MODIFY_PHONE_STATE)
+    public void setDefaultDataSubId(int subscriptionId) {
+        if (VDBG) logd("setDataSubscription sub id = " + subscriptionId);
         try {
             ISub iSub = ISub.Stub.asInterface(ServiceManager.getService("isub"));
             if (iSub != null) {
-                iSub.setDefaultDataSubId(subId);
+                iSub.setDefaultDataSubId(subscriptionId);
             }
         } catch (RemoteException ex) {
             // ignore it