diff --git a/clients/client-s3/src/protocols/Aws_restXml.ts b/clients/client-s3/src/protocols/Aws_restXml.ts
index 279f1fcc8bbc..95fc3f89b58d 100644
--- a/clients/client-s3/src/protocols/Aws_restXml.ts
+++ b/clients/client-s3/src/protocols/Aws_restXml.ts
@@ -8579,7 +8579,7 @@ const serializeAws_restXmlLambdaFunctionConfigurationList = (
 const serializeAws_restXmlLifecycleExpiration = (input: LifecycleExpiration, context: __SerdeContext): any => {
   const bodyNode = new __XmlNode("LifecycleExpiration");
   if (input.Date != null) {
-    const node = __XmlNode.of("Date", input.Date.toISOString().split(".")[0] + "Z").withName("Date");
+    const node = __XmlNode.of("Date", (input.Date.toISOString().split(".")[0] + "Z").toString()).withName("Date");
     bodyNode.addChildNode(node);
   }
   if (input.Days != null) {
@@ -8980,7 +8980,7 @@ const serializeAws_restXmlObjectLockRetention = (input: ObjectLockRetention, con
   }
   if (input.RetainUntilDate != null) {
     const node = __XmlNode
-      .of("Date", input.RetainUntilDate.toISOString().split(".")[0] + "Z")
+      .of("Date", (input.RetainUntilDate.toISOString().split(".")[0] + "Z").toString())
       .withName("RetainUntilDate");
     bodyNode.addChildNode(node);
   }
@@ -9729,7 +9729,7 @@ const serializeAws_restXmlTopicConfigurationList = (input: TopicConfiguration[],
 const serializeAws_restXmlTransition = (input: Transition, context: __SerdeContext): any => {
   const bodyNode = new __XmlNode("Transition");
   if (input.Date != null) {
-    const node = __XmlNode.of("Date", input.Date.toISOString().split(".")[0] + "Z").withName("Date");
+    const node = __XmlNode.of("Date", (input.Date.toISOString().split(".")[0] + "Z").toString()).withName("Date");
     bodyNode.addChildNode(node);
   }
   if (input.Days != null) {
diff --git a/codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/XmlShapeSerVisitor.java b/codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/XmlShapeSerVisitor.java
index 6295b51801b6..05bef81c14aa 100644
--- a/codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/XmlShapeSerVisitor.java
+++ b/codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/XmlShapeSerVisitor.java
@@ -16,6 +16,7 @@
 package software.amazon.smithy.aws.typescript.codegen;
 
 import java.util.Map;
+import java.util.Optional;
 import java.util.function.Supplier;
 import software.amazon.smithy.codegen.core.CodegenException;
 import software.amazon.smithy.model.Model;
@@ -236,17 +237,20 @@ void serializeNamedMember(
             // Grab the target shape so we can use a member serializer on it.
             Shape target = context.getModel().expectShape(memberShape.getTarget());
             XmlMemberSerVisitor inputVisitor = getMemberVisitor(inputLocation.get());
-
             // Collected members must be handled with flattening and renaming.
             if (serializationReturnsArray(target)) {
                 serializeNamedMemberFromArray(context, locationName, memberShape, target, inputVisitor);
             } else {
                 // Handle @timestampFormat on members not just the targeted shape.
                 String valueProvider;
-                if (memberShape.hasTrait(TimestampFormatTrait.class)) {
+                if (memberShape.hasTrait(TimestampFormatTrait.class) || target.hasTrait(TimestampFormatTrait.class)) {
+                    Optional<TimestampFormatTrait> timestampFormat = memberShape.getTrait(TimestampFormatTrait.class);
+                    if (timestampFormat.isEmpty()) {
+                        timestampFormat = target.getTrait(TimestampFormatTrait.class);
+                    }
                     valueProvider = inputVisitor.getAsXmlText(target,
                             AwsProtocolUtils.getInputTimestampValueProvider(context, memberShape,
-                                    TIMESTAMP_FORMAT, inputLocation.get()) + ".toString()");
+                                    timestampFormat.get().getFormat(), inputLocation.get()) + ".toString()");
                 } else {
                     valueProvider = target.accept(inputVisitor);
                 }