diff --git a/csharp/src/Google.Protobuf.Test/MessageExtensionsTest.cs b/csharp/src/Google.Protobuf.Test/MessageExtensionsTest.cs
new file mode 100644
index 0000000000000..e217881419d21
--- /dev/null
+++ b/csharp/src/Google.Protobuf.Test/MessageExtensionsTest.cs
@@ -0,0 +1,22 @@
+using System.IO;
+using Google.Protobuf.Buffers;
+using Google.Protobuf.TestProtos;
+using NUnit.Framework;
+
+namespace Google.Protobuf;
+
+public class MessageExtensionsTest
+{
+    [Test]
+    public void TestWriteDelimitedToRoundTripWithBufferWriter()
+    {
+        TestWellKnownTypes message = new() { Int32Field = 25 };
+
+        TestArrayBufferWriter<byte> buffer = new();
+        message.WriteDelimitedTo(buffer);
+
+        Assert.That(
+            TestWellKnownTypes.Parser.ParseDelimitedFrom(new MemoryStream(buffer.WrittenSpan.ToArray())),
+            Is.EqualTo(message));
+    }
+}
\ No newline at end of file
diff --git a/csharp/src/Google.Protobuf/MessageExtensions.cs b/csharp/src/Google.Protobuf/MessageExtensions.cs
index 910c40ff96df9..aec47415b8b9f 100644
--- a/csharp/src/Google.Protobuf/MessageExtensions.cs
+++ b/csharp/src/Google.Protobuf/MessageExtensions.cs
@@ -157,6 +157,23 @@ public static void WriteTo(this IMessage message, IBufferWriter<byte> output)
             ctx.Flush();
         }
 
+        /// <summary>
+        /// Writes the length and then data of the given message to a buffer writer.
+        /// </summary>
+        /// <param name="message">The message to write.</param>
+        /// <param name="output">The buffer writer.</param>
+        [SecuritySafeCritical]
+        public static void WriteDelimitedTo(this IMessage message, IBufferWriter<byte> output)
+        {
+            ProtoPreconditions.CheckNotNull(message, nameof(message));
+            ProtoPreconditions.CheckNotNull(output, nameof(output));
+
+            WriteContext.Initialize(output, out WriteContext ctx);
+            ctx.WriteLength(message.CalculateSize());
+            WritingPrimitivesMessages.WriteRawMessage(ref ctx, message);
+            ctx.Flush();
+        }
+
         /// <summary>
         /// Writes the given message data to the given span in protobuf encoding.
         /// The size of the destination span needs to fit the serialized size