diff --git a/android/guava/src/com/google/common/collect/ImmutableSortedSet.java b/android/guava/src/com/google/common/collect/ImmutableSortedSet.java
index 15963e4d9d05..53aa84b77a48 100644
--- a/android/guava/src/com/google/common/collect/ImmutableSortedSet.java
+++ b/android/guava/src/com/google/common/collect/ImmutableSortedSet.java
@@ -663,6 +663,22 @@ public E last() {
     return descendingIterator().next();
   }
 
+  /**
+   * @since NEXT. Note, however, that Java 21 users can call this method with any version of Guava.
+   */
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  public final E getFirst() {
+    return first();
+  }
+
+  /**
+   * @since NEXT. Note, however, that Java 21 users can call this method with any version of Guava.
+   */
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  public final E getLast() {
+    return last();
+  }
+
   /**
    * Guaranteed to throw an exception and leave the set unmodified.
    *
@@ -697,6 +713,68 @@ public final E pollLast() {
     throw new UnsupportedOperationException();
   }
 
+  /**
+   * Guaranteed to throw an exception and leave the set unmodified.
+   *
+   * @since NEXT
+   * @throws UnsupportedOperationException always
+   * @deprecated Unsupported operation.
+   */
+  @CanIgnoreReturnValue
+  @Deprecated
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  @DoNotCall("Always throws UnsupportedOperationException")
+  @CheckForNull
+  public final E removeFirst() {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * Guaranteed to throw an exception and leave the set unmodified.
+   *
+   * @since NEXT
+   * @throws UnsupportedOperationException always
+   * @deprecated Unsupported operation.
+   */
+  @CanIgnoreReturnValue
+  @Deprecated
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  @DoNotCall("Always throws UnsupportedOperationException")
+  @CheckForNull
+  public final E removeLast() {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * Guaranteed to throw an exception and leave the set unmodified.
+   *
+   * @since NEXT
+   * @throws UnsupportedOperationException always
+   * @deprecated Unsupported operation.
+   */
+  @Deprecated
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  @DoNotCall("Always throws UnsupportedOperationException")
+  @CheckForNull
+  public final void addFirst(E e) {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * Guaranteed to throw an exception and leave the set unmodified.
+   *
+   * @since NEXT
+   * @throws UnsupportedOperationException always
+   * @deprecated Unsupported operation.
+   */
+  @Deprecated
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  @DoNotCall("Always throws UnsupportedOperationException")
+  @CheckForNull
+  public final void addLast(E e) {
+    throw new UnsupportedOperationException();
+  }
+
   @GwtIncompatible // NavigableSet
   @LazyInit
   @CheckForNull
@@ -715,6 +793,16 @@ public ImmutableSortedSet<E> descendingSet() {
     return result;
   }
 
+  /**
+   * @since NEXT. Note, however, that a variant of this method with return type {@link NavigableSet}
+   *     is available to Java 21 users with any version of Guava.
+   */
+  @GwtIncompatible // NavigableSet
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  public final ImmutableSortedSet<E> reversed() {
+    return descendingSet();
+  }
+
   // Most classes should implement this as new DescendingImmutableSortedSet<E>(this),
   // but we push down that implementation because ProGuard can't eliminate it even when it's always
   // overridden.
diff --git a/guava/src/com/google/common/collect/ImmutableSortedSet.java b/guava/src/com/google/common/collect/ImmutableSortedSet.java
index b06de212bbb7..3ec7e0f4d9ed 100644
--- a/guava/src/com/google/common/collect/ImmutableSortedSet.java
+++ b/guava/src/com/google/common/collect/ImmutableSortedSet.java
@@ -731,6 +731,22 @@ public E last() {
     return descendingIterator().next();
   }
 
+  /**
+   * @since NEXT. Note, however, that Java 21 users can call this method with any version of Guava.
+   */
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  public final E getFirst() {
+    return first();
+  }
+
+  /**
+   * @since NEXT. Note, however, that Java 21 users can call this method with any version of Guava.
+   */
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  public final E getLast() {
+    return last();
+  }
+
   /**
    * Guaranteed to throw an exception and leave the set unmodified.
    *
@@ -765,6 +781,68 @@ public final E pollLast() {
     throw new UnsupportedOperationException();
   }
 
+  /**
+   * Guaranteed to throw an exception and leave the set unmodified.
+   *
+   * @since NEXT
+   * @throws UnsupportedOperationException always
+   * @deprecated Unsupported operation.
+   */
+  @CanIgnoreReturnValue
+  @Deprecated
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  @DoNotCall("Always throws UnsupportedOperationException")
+  @CheckForNull
+  public final E removeFirst() {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * Guaranteed to throw an exception and leave the set unmodified.
+   *
+   * @since NEXT
+   * @throws UnsupportedOperationException always
+   * @deprecated Unsupported operation.
+   */
+  @CanIgnoreReturnValue
+  @Deprecated
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  @DoNotCall("Always throws UnsupportedOperationException")
+  @CheckForNull
+  public final E removeLast() {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * Guaranteed to throw an exception and leave the set unmodified.
+   *
+   * @since NEXT
+   * @throws UnsupportedOperationException always
+   * @deprecated Unsupported operation.
+   */
+  @Deprecated
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  @DoNotCall("Always throws UnsupportedOperationException")
+  @CheckForNull
+  public final void addFirst(E e) {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * Guaranteed to throw an exception and leave the set unmodified.
+   *
+   * @since NEXT
+   * @throws UnsupportedOperationException always
+   * @deprecated Unsupported operation.
+   */
+  @Deprecated
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  @DoNotCall("Always throws UnsupportedOperationException")
+  @CheckForNull
+  public final void addLast(E e) {
+    throw new UnsupportedOperationException();
+  }
+
   @GwtIncompatible // NavigableSet
   @LazyInit
   @CheckForNull
@@ -783,6 +861,16 @@ public ImmutableSortedSet<E> descendingSet() {
     return result;
   }
 
+  /**
+   * @since NEXT. Note, however, that a variant of this method with return type {@link NavigableSet}
+   *     is available to Java 21 users with any version of Guava.
+   */
+  @GwtIncompatible // NavigableSet
+  @SuppressWarnings("MissingOverride") // only an override under JDK 21+
+  public final ImmutableSortedSet<E> reversed() {
+    return descendingSet();
+  }
+
   // Most classes should implement this as new DescendingImmutableSortedSet<E>(this),
   // but we push down that implementation because ProGuard can't eliminate it even when it's always
   // overridden.