diff --git a/api/current.txt b/api/current.txt
index 7acbdb4..0c5aa20 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -48111,7 +48111,7 @@
     method public long getDataLimitBytes();
     method public long getDataUsageBytes();
     method public long getDataUsageTime();
-    method @Nullable public int[] getNetworkTypes();
+    method @NonNull public int[] getNetworkTypes();
     method @Nullable public CharSequence getSummary();
     method @Nullable public CharSequence getTitle();
     method public void writeToParcel(android.os.Parcel, int);
@@ -48131,7 +48131,7 @@
     method public static android.telephony.SubscriptionPlan.Builder createRecurring(java.time.ZonedDateTime, java.time.Period);
     method public android.telephony.SubscriptionPlan.Builder setDataLimit(long, int);
     method public android.telephony.SubscriptionPlan.Builder setDataUsage(long, long);
-    method @NonNull public android.telephony.SubscriptionPlan.Builder setNetworkTypes(@Nullable int[]);
+    method @NonNull public android.telephony.SubscriptionPlan.Builder setNetworkTypes(@NonNull int[]);
     method public android.telephony.SubscriptionPlan.Builder setSummary(@Nullable CharSequence);
     method public android.telephony.SubscriptionPlan.Builder setTitle(@Nullable CharSequence);
   }
diff --git a/core/java/android/telephony/SubscriptionPlan.java b/core/java/android/telephony/SubscriptionPlan.java
index ff2f4ad..901957f 100644
--- a/core/java/android/telephony/SubscriptionPlan.java
+++ b/core/java/android/telephony/SubscriptionPlan.java
@@ -91,10 +91,11 @@
     private long dataUsageBytes = BYTES_UNKNOWN;
     private long dataUsageTime = TIME_UNKNOWN;
     private @NetworkType int[] networkTypes;
-    private long networkTypesBitMask;
 
     private SubscriptionPlan(RecurrenceRule cycleRule) {
         this.cycleRule = Preconditions.checkNotNull(cycleRule);
+        this.networkTypes = Arrays.copyOf(TelephonyManager.getAllNetworkTypes(),
+                TelephonyManager.getAllNetworkTypes().length);
     }
 
     private SubscriptionPlan(Parcel source) {
@@ -221,10 +222,10 @@
 
     /**
      * Return an array containing all {@link NetworkType}s this SubscriptionPlan applies to.
-     * A null value means this SubscriptionPlan applies to all network types.
+     * @see TelephonyManager for network types values
      */
-    public @Nullable @NetworkType int[] getNetworkTypes() {
-        return networkTypes;
+    public @NonNull @NetworkType int[] getNetworkTypes() {
+        return Arrays.copyOf(networkTypes, networkTypes.length);
     }
 
     /**
@@ -361,14 +362,14 @@
         }
 
         /**
-         * Set the network types this SubscriptionPlan applies to.
+         * Set the network types this SubscriptionPlan applies to. By default the plan will apply
+         * to all network types. An empty array means this plan applies to no network types.
          *
-         * @param networkTypes a set of all {@link NetworkType}s that apply to this plan.
-         *            A null value means the plan applies to all network types,
-         *            and an empty array means the plan applies to no network types.
+         * @param networkTypes an array of all {@link NetworkType}s that apply to this plan.
+         * @see TelephonyManager for network type values
          */
-        public @NonNull Builder setNetworkTypes(@Nullable @NetworkType int[] networkTypes) {
-            plan.networkTypes = networkTypes;
+        public @NonNull Builder setNetworkTypes(@NonNull @NetworkType int[] networkTypes) {
+            plan.networkTypes = Arrays.copyOf(networkTypes, networkTypes.length);
             return this;
         }
     }
diff --git a/services/core/java/com/android/server/net/NetworkPolicyManagerService.java b/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
index 0b1c91f..ea41122 100644
--- a/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
+++ b/services/core/java/com/android/server/net/NetworkPolicyManagerService.java
@@ -3087,17 +3087,38 @@
     private void enforceSubscriptionPlanValidity(SubscriptionPlan[] plans) {
         // nothing to check if no plans
         if (plans.length == 0) {
+            Log.d(TAG, "Received empty plans list. Clearing existing SubscriptionPlans.");
             return;
         }
 
-        final ArraySet<Integer> applicableNetworkTypes = new ArraySet<Integer>();
-        boolean allNetworks = false;
-        for (SubscriptionPlan plan : plans) {
-            if (plan.getNetworkTypes() == null) {
-                allNetworks = true;
+        final int[] allNetworkTypes = TelephonyManager.getAllNetworkTypes();
+        final ArraySet<Integer> allNetworksSet = new ArraySet<>();
+        addAll(allNetworksSet, allNetworkTypes);
+
+        final ArraySet<Integer> applicableNetworkTypes = new ArraySet<>();
+        boolean hasGeneralPlan = false;
+        for (int i = 0; i < plans.length; i++) {
+            final int[] planNetworkTypes = plans[i].getNetworkTypes();
+            final ArraySet<Integer> planNetworksSet = new ArraySet<>();
+            for (int j = 0; j < planNetworkTypes.length; j++) {
+                // ensure all network types are valid
+                if (allNetworksSet.contains(planNetworkTypes[j])) {
+                    // ensure no duplicate network types in the same SubscriptionPlan
+                    if (!planNetworksSet.add(planNetworkTypes[j])) {
+                        throw new IllegalArgumentException(
+                                "Subscription plan contains duplicate network types.");
+                    }
+                } else {
+                    throw new IllegalArgumentException("Invalid network type: "
+                            + planNetworkTypes[j]);
+                }
+            }
+
+            if (planNetworkTypes.length == allNetworkTypes.length) {
+                hasGeneralPlan = true;
             } else {
-                final int[] networkTypes = plan.getNetworkTypes();
-                if (!addAll(applicableNetworkTypes, networkTypes)) {
+                // ensure no network type applies to multiple plans
+                if (!addAll(applicableNetworkTypes, planNetworkTypes)) {
                     throw new IllegalArgumentException(
                             "Multiple subscription plans defined for a single network type.");
                 }
@@ -3105,7 +3126,7 @@
         }
 
         // ensure at least one plan applies for every network type
-        if (!allNetworks) {
+        if (!hasGeneralPlan) {
             throw new IllegalArgumentException(
                     "No generic subscription plan that applies to all network types.");
         }
@@ -3114,12 +3135,12 @@
     /**
      * Adds all of the {@code elements} to the {@code set}.
      *
-     * @return {@code false} if any element is not added because the set already have the value.
+     * @return {@code false} if any element is not added because the set already has the value.
      */
-    private static boolean addAll(@NonNull Set<Integer> set, @NonNull int... elements) {
+    private static boolean addAll(@NonNull ArraySet<Integer> set, @NonNull int... elements) {
         boolean result = true;
-        for (int element : elements) {
-            result &= set.add(element);
+        for (int i = 0; i < elements.length; i++) {
+            result &= set.add(elements[i]);
         }
         return result;
     }