diff --git a/codegen/smithy-aws-swift-codegen/src/main/kotlin/software/amazon/smithy/aws/swift/codegen/customization/RulesBasedAuthSchemeResolverGenerator.kt b/codegen/smithy-aws-swift-codegen/src/main/kotlin/software/amazon/smithy/aws/swift/codegen/customization/RulesBasedAuthSchemeResolverGenerator.kt
index b0780b93581..a4d2c608edd 100644
--- a/codegen/smithy-aws-swift-codegen/src/main/kotlin/software/amazon/smithy/aws/swift/codegen/customization/RulesBasedAuthSchemeResolverGenerator.kt
+++ b/codegen/smithy-aws-swift-codegen/src/main/kotlin/software/amazon/smithy/aws/swift/codegen/customization/RulesBasedAuthSchemeResolverGenerator.kt
@@ -222,6 +222,8 @@ class RulesBasedAuthSchemeResolverGenerator {
                     )
                 }
 
+                writer.write("let authSchemePreference = context.getAuthSchemePreference()")
+
                 // Copy over endpoint param fields to auth param fields
                 val ruleSetNode = ctx.service.getTrait<EndpointRuleSetTrait>()?.ruleSet
                 val ruleSet = if (ruleSetNode != null) EndpointRuleSet.fromNode(ruleSetNode) else null
@@ -234,7 +236,7 @@ class RulesBasedAuthSchemeResolverGenerator {
                 }
 
                 val argStringToAppend = if (paramList.isEmpty()) "" else ", " + paramList.joinToString()
-                write("return $returnTypeName(operation: opName$argStringToAppend)")
+                write("return $returnTypeName(authSchemePreference: authSchemePreference, operation: opName$argStringToAppend)")
             }
         }
     }
diff --git a/codegen/smithy-aws-swift-codegen/src/test/kotlin/software/amazon/smithy/aws/swift/codegen/customizations/RulesBasedAuthSchemeResolverGeneratorTests.kt b/codegen/smithy-aws-swift-codegen/src/test/kotlin/software/amazon/smithy/aws/swift/codegen/customizations/RulesBasedAuthSchemeResolverGeneratorTests.kt
index 148a53fe2af..69c00e2d103 100644
--- a/codegen/smithy-aws-swift-codegen/src/test/kotlin/software/amazon/smithy/aws/swift/codegen/customizations/RulesBasedAuthSchemeResolverGeneratorTests.kt
+++ b/codegen/smithy-aws-swift-codegen/src/test/kotlin/software/amazon/smithy/aws/swift/codegen/customizations/RulesBasedAuthSchemeResolverGeneratorTests.kt
@@ -21,6 +21,7 @@ class RulesBasedAuthSchemeResolverGeneratorTests {
         contents.shouldSyntacticSanityCheck()
         val expectedContents = """
 public struct S3AuthSchemeResolverParameters: SmithyHTTPAuthAPI.AuthSchemeResolverParameters {
+    public let authSchemePreference: [String]?
     public let operation: Swift.String
 }
 
@@ -32,12 +33,6 @@ public protocol S3AuthSchemeResolver: SmithyHTTPAuthAPI.AuthSchemeResolver {
 
 private struct InternalModeledS3AuthSchemeResolver: S3AuthSchemeResolver {
 
-    public let authSchemePreference: [String]
-
-    public init(authSchemePreference: [String] = []) {
-        self.authSchemePreference = authSchemePreference
-    }
-
     public func resolveAuthScheme(params: SmithyHTTPAuthAPI.AuthSchemeResolverParameters) throws -> [SmithyHTTPAuthAPI.AuthOption] {
         var validAuthOptions = [SmithyHTTPAuthAPI.AuthOption]()
         guard let serviceParams = params as? S3AuthSchemeResolverParameters else {
@@ -140,7 +135,7 @@ private struct InternalModeledS3AuthSchemeResolver: S3AuthSchemeResolver {
                 sigv4Option.identityProperties.set(key: AWSSDKIdentity.InternalClientKeys.internalSSOOIDCClientKey, value: InternalAWSSSOOIDC.IdentityProvidingSSOOIDCClient())
                 validAuthOptions.append(sigv4Option)
         }
-        return self.reprioritizeAuthOptions(authSchemePreference: authSchemePreference, authOptions: validAuthOptions)
+        return self.reprioritizeAuthOptions(authSchemePreference: serviceParams.authSchemePreference, authOptions: validAuthOptions)
     }
 
     public func constructParameters(context: Smithy.Context) throws -> SmithyHTTPAuthAPI.AuthSchemeResolverParameters {
@@ -200,7 +195,8 @@ public struct DefaultS3AuthSchemeResolver: S3AuthSchemeResolver {
         guard let endpointParam = context.get(key: Smithy.AttributeKey<EndpointParams>(name: "EndpointParams")) else {
             throw Smithy.ClientError.dataNotFound("Endpoint param not configured in middleware context for rules-based auth scheme resolver params construction.")
         }
-        return S3AuthSchemeResolverParameters(operation: opName)
+        let authSchemePreference = context.getAuthSchemePreference()
+        return S3AuthSchemeResolverParameters(authSchemePreference: authSchemePreference, operation: opName)
     }
 }
 """