diff --git a/telecomm/java/android/telecom/PhoneAccount.java b/telecomm/java/android/telecom/PhoneAccount.java
index b8c056e4bb109..ca15422a848fc 100644
--- a/telecomm/java/android/telecom/PhoneAccount.java
+++ b/telecomm/java/android/telecom/PhoneAccount.java
@@ -540,6 +540,11 @@ public final class PhoneAccount implements Parcelable {
 
         /**
          * Creates a builder with the specified {@link PhoneAccountHandle} and label.
+         * <p>
+         * Note: each CharSequence or String field is limited to 256 characters. This check is
+         * enforced when registering the PhoneAccount via
+         * {@link TelecomManager#registerPhoneAccount(PhoneAccount)} and will cause an
+         * {@link IllegalArgumentException} to be thrown if the character field limit is over 256.
          */
         public Builder(PhoneAccountHandle accountHandle, CharSequence label) {
             this.mAccountHandle = accountHandle;
@@ -570,6 +575,11 @@ public final class PhoneAccount implements Parcelable {
 
         /**
          * Sets the label. See {@link PhoneAccount#getLabel()}.
+         * <p>
+         * Note: Each CharSequence or String field is limited to 256 characters. This check is
+         * enforced when registering the PhoneAccount via
+         * {@link TelecomManager#registerPhoneAccount(PhoneAccount)} and will cause an
+         * {@link IllegalArgumentException} to be thrown if the character field limit is over 256.
          *
          * @param label The label of the phone account.
          * @return The builder.
@@ -636,6 +646,11 @@ public final class PhoneAccount implements Parcelable {
 
         /**
          * Sets the short description. See {@link PhoneAccount#getShortDescription}.
+         * <p>
+         * Note: Each CharSequence or String field is limited to 256 characters. This check is
+         * enforced when registering the PhoneAccount via
+         * {@link TelecomManager#registerPhoneAccount(PhoneAccount)} and will cause an
+         * {@link IllegalArgumentException} to be thrown if the character field limit is over 256.
          *
          * @param value The short description.
          * @return The builder.
@@ -680,6 +695,13 @@ public final class PhoneAccount implements Parcelable {
          * <p>
          * {@code PhoneAccount}s only support extra values of type: {@link String}, {@link Integer},
          * and {@link Boolean}.  Extras which are not of these types are ignored.
+         * <p>
+         * Note: Each Bundle (Key, Value) String field is limited to 256 characters. Additionally,
+         * the bundle is limited to 100 (Key, Value) pairs total.  This check is
+         * enforced when registering the PhoneAccount via
+         * {@link TelecomManager#registerPhoneAccount(PhoneAccount)} and will cause an
+         * {@link IllegalArgumentException} to be thrown if the character field limit is over 256
+         * or more than 100 (Key, Value) pairs are in the Bundle.
          *
          * @param extras
          * @return
@@ -711,6 +733,11 @@ public final class PhoneAccount implements Parcelable {
          * <p>
          * Note: This is an API specific to the Telephony stack; the group Id will be ignored for
          * callers not holding the correct permission.
+         * <p>
+         * Additionally, each CharSequence or String field is limited to 256 characters.
+         * This check is enforced when registering the PhoneAccount via
+         * {@link TelecomManager#registerPhoneAccount(PhoneAccount)} and will cause an
+         * {@link IllegalArgumentException} to be thrown if the character field limit is over 256.
          *
          * @param groupId The group Id of the {@link PhoneAccount} that will replace any other
          * registered {@link PhoneAccount} in Telecom with the same Group Id.
diff --git a/telecomm/java/android/telecom/PhoneAccountHandle.java b/telecomm/java/android/telecom/PhoneAccountHandle.java
index ec94f8a1829fd..e5db8cfa0989f 100644
--- a/telecomm/java/android/telecom/PhoneAccountHandle.java
+++ b/telecomm/java/android/telecom/PhoneAccountHandle.java
@@ -70,6 +70,12 @@ public final class PhoneAccountHandle implements Parcelable {
      *           ID provided does not expose personally identifying information.  A
      *           {@link ConnectionService} should use an opaque token as the
      *           {@link PhoneAccountHandle} identifier.
+     * <p>
+     * Note: Each String field is limited to 256 characters. This check is enforced when
+     *           registering the PhoneAccount via
+     *           {@link TelecomManager#registerPhoneAccount(PhoneAccount)} and will cause an
+     *           {@link IllegalArgumentException} to be thrown if the character field limit is
+     *           over 256.
      */
     public PhoneAccountHandle(
             @NonNull ComponentName componentName,
@@ -88,6 +94,13 @@ public final class PhoneAccountHandle implements Parcelable {
      *           {@link ConnectionService} should use an opaque token as the
      *           {@link PhoneAccountHandle} identifier.
      * @param userHandle The {@link UserHandle} associated with this {@link PhoneAccountHandle}.
+     *
+     * <p>
+     * Note: Each String field is limited to 256 characters. This check is enforced when
+     *           registering the PhoneAccount via
+     *           {@link TelecomManager#registerPhoneAccount(PhoneAccount)} and will cause an
+     *           {@link IllegalArgumentException} to be thrown if the character field limit is
+     *           over 256.
      */
     public PhoneAccountHandle(
             @NonNull ComponentName componentName,