diff --git a/packages/middleware-sdk-s3/src/s3-type-transforms.integ.spec.ts b/packages/middleware-sdk-s3/src/s3-type-transforms.integ.spec.ts
new file mode 100644
index 0000000000000..a8e9430be8778
--- /dev/null
+++ b/packages/middleware-sdk-s3/src/s3-type-transforms.integ.spec.ts
@@ -0,0 +1,210 @@
+import { GetObjectCommand, GetObjectCommandInput, S3, S3Client } from "@aws-sdk/client-s3";
+import type { AssertiveClient, BrowserClient, NodeJsClient, NoUndefined, UncheckedClient } from "@smithy/types";
+
+describe("S3 client transform integration test", () => {
+  it("has the expected compilation behavior", async () => {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    async function compileOnly() {
+      // default, no validation for undefined values
+      const s3 = new S3({});
+
+      await s3.listBuckets();
+      await s3.listBuckets({});
+
+      // @ts-expect-error (missing Bucket)
+      s3.getObject({
+        Key: undefined,
+      });
+
+      s3.getObject({
+        // @ts-expect-error (unrecognized field)
+        UnknownProperty: undefined,
+      });
+
+      const get = await s3.getObject({
+        Bucket: undefined,
+        Key: undefined,
+      });
+
+      // @ts-expect-error (Body may be undefined)
+      await get.Body.transformToString();
+
+      await get.Body?.transformToString();
+      await get.Body!.transformToString();
+    }
+  });
+
+  it("assertive client transform", async () => {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    async function compileOnly() {
+      // the assertive client requires that inputs/outputs are of the right type
+      // excluding '| undefined'.
+      const s3_assertive = new S3() as AssertiveClient<S3>;
+      const s3Client_assertive = new S3Client() as AssertiveClient<S3Client>;
+
+      await s3_assertive.listBuckets();
+      await s3_assertive.listBuckets({});
+
+      s3_assertive.getObject({
+        Bucket: "undefined",
+        // @ts-expect-error (undefined not assignable to string)
+        Key: undefined,
+      });
+      s3Client_assertive.send(
+        new GetObjectCommand({
+          Bucket: "undefined",
+          // type transform is unable to validate within Command ctor.
+          Key: undefined,
+        })
+      );
+
+      {
+        const getObjectInput: NoUndefined<GetObjectCommandInput> = {
+          Bucket: "undefined",
+          // @ts-expect-error (undefined not assignable to string)
+          Key: undefined,
+          // optional params can still be undefined.
+          SSECustomerAlgorithm: undefined,
+        };
+        const get = await s3Client_assertive.send(new GetObjectCommand(getObjectInput));
+        // @ts-expect-error (Body is possibly undefined)
+        await get.Body.transformToString();
+      }
+
+      // @ts-expect-error (missing Key)
+      s3_assertive.getObject({
+        Bucket: "undefined",
+      });
+
+      {
+        const get = await s3_assertive.getObject({
+          Bucket: "undefined",
+          Key: "undefined",
+        });
+
+        // @ts-expect-error (Body is optional)
+        await get.Body.transformToString();
+
+        await get.Body?.transformToString();
+        await get.Body!.transformToString();
+      }
+
+      {
+        const get = await s3Client_assertive.send(
+          new GetObjectCommand({
+            Bucket: "undefined",
+            Key: "undefined",
+          })
+        );
+
+        // @ts-expect-error (Body is optional)
+        await get.Body.transformToString();
+
+        await get.Body?.transformToString();
+        await get.Body!.transformToString();
+      }
+    }
+  });
+
+  it("unchecked client transform", async () => {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    async function compileOnly() {
+      // unchecked client also removes the possibility
+      // of optionality '?' in addition to '| undefined'.
+      const s3_unchecked = new S3({}) as UncheckedClient<S3>;
+      const s3Client_unchecked = new S3Client() as UncheckedClient<S3Client>;
+
+      await s3_unchecked.listBuckets();
+      await s3_unchecked.listBuckets({});
+
+      s3_unchecked.getObject({
+        Bucket: "undefined",
+        // @ts-expect-error (undefined not assignable to string)
+        Key: undefined,
+      });
+      s3_unchecked.send(
+        new GetObjectCommand({
+          Bucket: "undefined",
+          // type transform is unable to validate within Command ctor.
+          Key: undefined,
+        })
+      );
+
+      {
+        const getObjectInput: NoUndefined<GetObjectCommandInput> = {
+          Bucket: "undefined",
+          // @ts-expect-error (undefined not assignable to string)
+          Key: undefined,
+          // optional params can still be undefined.
+          SSECustomerAlgorithm: undefined,
+        };
+        const get = await s3Client_unchecked.send(new GetObjectCommand(getObjectInput));
+        await get.Body.transformToString();
+      }
+
+      // @ts-expect-error (missing Key)
+      s3_unchecked.getObject({
+        Bucket: "undefined",
+      });
+
+      {
+        const get = await s3_unchecked.getObject({
+          Bucket: "undefined",
+          Key: "undefined",
+        });
+
+        await get.Body.transformToString();
+      }
+
+      {
+        const get = await s3Client_unchecked.send(
+          new GetObjectCommand({
+            Bucket: "undefined",
+            Key: "undefined",
+          })
+        );
+
+        await get.Body.transformToString();
+      }
+    }
+  });
+
+  it("platform-specific client transforms", async () => {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    async function compileOnly() {
+      // platform specific clients.
+      const s3_browser = new S3({}) as BrowserClient<S3>;
+      const s3Client_browser = new S3Client() as BrowserClient<S3Client>;
+      const s3_node = new S3() as NodeJsClient<S3>;
+      const s3Client_node = new S3() as NodeJsClient<S3>;
+
+      {
+        const get = await s3Client_browser.send(
+          new GetObjectCommand({
+            Bucket: "undefined",
+            Key: "undefined",
+          })
+        );
+        get.Body!.tee();
+      }
+      {
+        const get = await s3_browser.getObject({ Bucket: "undefined", Key: "undefined" });
+        get.Body!.tee();
+      }
+
+      {
+        const get = await s3Client_node.send(
+          new GetObjectCommand({
+            Bucket: "undefined",
+            Key: "undefined",
+          })
+        );
+        get.Body!.pause();
+      }
+      {
+        const get = await s3_node.getObject({ Bucket: "undefined", Key: "undefined" });
+        get.Body!.pause();
+      }
+    }
+  });
+});