diff --git a/PolyShim/NetCore30/Stream.cs b/PolyShim/NetCore30/Stream.cs
new file mode 100644
index 0000000..668f110
--- /dev/null
+++ b/PolyShim/NetCore30/Stream.cs
@@ -0,0 +1,33 @@
+#if (NETCOREAPP && !NETCOREAPP3_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD && !NETSTANDARD2_1_OR_GREATER)
+#nullable enable
+// ReSharper disable RedundantUsingDirective
+// ReSharper disable CheckNamespace
+// ReSharper disable InconsistentNaming
+// ReSharper disable PartialTypeWithSinglePart
+
+using System;
+using System.IO;
+using System.Threading.Tasks;
+
+internal static partial class PolyfillExtensions
+{
+    extension(Stream stream)
+    {
+#if FEATURE_TASK
+        // https://learn.microsoft.com/dotnet/api/system.io.stream.disposeasync
+        public async Task DisposeAsync()
+        {
+#if FEATURE_ASYNCINTERFACES
+            if (stream is IAsyncDisposable asyncDisposable)
+            {
+                await asyncDisposable.DisposeAsync();
+                return;
+            }
+#endif
+
+            await Task.Run(stream.Dispose);
+        }
+#endif
+    }
+}
+#endif
diff --git a/PolyShim/NetCore30/TextReader.cs b/PolyShim/NetCore30/TextReader.cs
new file mode 100644
index 0000000..cd552b3
--- /dev/null
+++ b/PolyShim/NetCore30/TextReader.cs
@@ -0,0 +1,33 @@
+#if (NETCOREAPP && !NETCOREAPP3_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD && !NETSTANDARD2_1_OR_GREATER)
+#nullable enable
+// ReSharper disable RedundantUsingDirective
+// ReSharper disable CheckNamespace
+// ReSharper disable InconsistentNaming
+// ReSharper disable PartialTypeWithSinglePart
+
+using System;
+using System.IO;
+using System.Threading.Tasks;
+
+internal static partial class PolyfillExtensions
+{
+    extension(TextReader reader)
+    {
+#if FEATURE_TASK
+        // https://learn.microsoft.com/dotnet/api/system.io.textreader.disposeasync
+        public async Task DisposeAsync()
+        {
+#if FEATURE_ASYNCINTERFACES
+            if (reader is IAsyncDisposable asyncDisposable)
+            {
+                await asyncDisposable.DisposeAsync();
+                return;
+            }
+#endif
+
+            await Task.Run(reader.Dispose);
+        }
+#endif
+    }
+}
+#endif
diff --git a/PolyShim/NetCore30/TextWriter.cs b/PolyShim/NetCore30/TextWriter.cs
new file mode 100644
index 0000000..97d9ca9
--- /dev/null
+++ b/PolyShim/NetCore30/TextWriter.cs
@@ -0,0 +1,33 @@
+#if (NETCOREAPP && !NETCOREAPP3_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD && !NETSTANDARD2_1_OR_GREATER)
+#nullable enable
+// ReSharper disable RedundantUsingDirective
+// ReSharper disable CheckNamespace
+// ReSharper disable InconsistentNaming
+// ReSharper disable PartialTypeWithSinglePart
+
+using System;
+using System.IO;
+using System.Threading.Tasks;
+
+internal static partial class PolyfillExtensions
+{
+    extension(TextWriter writer)
+    {
+#if FEATURE_TASK
+        // https://learn.microsoft.com/dotnet/api/system.io.textwriter.disposeasync
+        public async Task DisposeAsync()
+        {
+#if FEATURE_ASYNCINTERFACES
+            if (writer is IAsyncDisposable asyncDisposable)
+            {
+                await asyncDisposable.DisposeAsync();
+                return;
+            }
+#endif
+
+            await Task.Run(writer.Dispose);
+        }
+#endif
+    }
+}
+#endif
diff --git a/PolyShim/Signatures.md b/PolyShim/Signatures.md
index 71c19e0..6e6e827 100644
--- a/PolyShim/Signatures.md
+++ b/PolyShim/Signatures.md
@@ -1,8 +1,8 @@
 # Signatures
 
-- **Total:** 333
+- **Total:** 336
 - **Types:** 74
-- **Members:** 259
+- **Members:** 262
 
 ___
 
@@ -318,6 +318,7 @@ ___
   - [`int Read(Span<byte>)`](https://learn.microsoft.com/dotnet/api/system.io.stream.read#system-io-stream-read(system-span((system-byte)))) <sup><sub>.NET Core 2.1</sub></sup>
   - [`int ReadAtLeast(Span<byte>, int, bool)`](https://learn.microsoft.com/dotnet/api/system.io.stream.readatleast) <sup><sub>.NET 7.0</sub></sup>
   - [`Task CopyToAsync(Stream, CancellationToken)`](https://learn.microsoft.com/dotnet/api/system.io.stream.copytoasync#system-io-stream-copytoasync(system-io-stream-system-threading-cancellationtoken)) <sup><sub>.NET Core 2.1</sub></sup>
+  - [`Task DisposeAsync()`](https://learn.microsoft.com/dotnet/api/system.io.stream.disposeasync) <sup><sub>.NET Core 3.0</sub></sup>
   - [`Task ReadExactlyAsync(byte[], int, int, CancellationToken)`](https://learn.microsoft.com/dotnet/api/system.io.stream.readexactlyasync#system-io-stream-readexactlyasync(system-byte()-system-int32-system-int32-system-threading-cancellationtoken)) <sup><sub>.NET 7.0</sub></sup>
   - [`Task ReadExactlyAsync(Memory<byte>, CancellationToken)`](https://learn.microsoft.com/dotnet/api/system.io.stream.readexactlyasync#system-io-stream-readexactlyasync(system-memory((system-byte))-system-threading-cancellationtoken)) <sup><sub>.NET 7.0</sub></sup>
   - [`Task WriteAsync(ReadOnlyMemory<byte>, CancellationToken)`](https://learn.microsoft.com/dotnet/api/system.io.stream.writeasync#system-io-stream-writeasync(system-readonlymemory((system-byte))-system-threading-cancellationtoken)) <sup><sub>.NET Core 2.1</sub></sup>
@@ -415,6 +416,10 @@ ___
 - `TaskCompletionSource<T>`
   - [`bool TrySetCanceled(CancellationToken)`](https://learn.microsoft.com/dotnet/api/system.threading.tasks.taskcompletionsource-1.trysetcanceled#system-threading-tasks-taskcompletionsource-1-trysetcanceled(system-threading-cancellationtoken)) <sup><sub>.NET Core 1.0</sub></sup>
   - [`void SetCanceled(CancellationToken)`](https://learn.microsoft.com/dotnet/api/system.threading.tasks.taskcompletionsource-1.setcanceled#system-threading-tasks-taskcompletionsource-1-setcanceled(system-threading-cancellationtoken)) <sup><sub>.NET 5.0</sub></sup>
+- `TextReader`
+  - [`Task DisposeAsync()`](https://learn.microsoft.com/dotnet/api/system.io.textreader.disposeasync) <sup><sub>.NET Core 3.0</sub></sup>
+- `TextWriter`
+  - [`Task DisposeAsync()`](https://learn.microsoft.com/dotnet/api/system.io.textwriter.disposeasync) <sup><sub>.NET Core 3.0</sub></sup>
 - `ThreadAbortException`
   - [**[class]**](https://learn.microsoft.com/dotnet/api/system.threading.threadabortexception) <sup><sub>.NET Core 2.0</sub></sup>
 - `TimeSpan`