diff --git a/packages/middleware-sdk-s3/src/s3-express/middleware-s3-express.integ.spec.ts b/packages/middleware-sdk-s3/src/s3-express/middleware-s3-express.integ.spec.ts
index ac069197b867..df2e2c89540c 100644
--- a/packages/middleware-sdk-s3/src/s3-express/middleware-s3-express.integ.spec.ts
+++ b/packages/middleware-sdk-s3/src/s3-express/middleware-s3-express.integ.spec.ts
@@ -20,6 +20,23 @@ describe("middleware-s3-express", () => {
   };
 
   describe(S3.name, () => {
+    it("should not send the x-amz-create-session-mode header", async () => {
+      const client = new S3({ region: "us-west-2", s3ExpressIdentityProvider });
+
+      requireRequestsFrom(client).toMatch({
+        headers: {
+          "x-amz-create-session-mode": /undefined/,
+        },
+      });
+
+      await client.getObject({
+        Bucket: "aws-sdk-js-v3-test--usw2-az1--x-s3",
+        Key: "1",
+      });
+
+      expect.hasAssertions();
+    });
+
     it("should default to CRC32 checksum when the request requires a checksum and none is specified", async () => {
       const client = new S3({ region: "us-west-2", s3ExpressIdentityProvider });
 
diff --git a/packages/middleware-sdk-s3/src/s3Configuration.ts b/packages/middleware-sdk-s3/src/s3Configuration.ts
index 4072a01dcaa4..6dfd9d3544ec 100644
--- a/packages/middleware-sdk-s3/src/s3Configuration.ts
+++ b/packages/middleware-sdk-s3/src/s3Configuration.ts
@@ -82,7 +82,6 @@ export const resolveS3Config = <T>(
         s3ClientProvider().send(
           new CreateSessionCommandCtor({
             Bucket: key,
-            SessionMode: "ReadWrite",
           })
         )
       ),