diff --git a/flutter_inappwebview_ios/ios/Classes/InAppWebView/InAppWebView.swift b/flutter_inappwebview_ios/ios/Classes/InAppWebView/InAppWebView.swift
index 52c0bae70..58e33151d 100755
--- a/flutter_inappwebview_ios/ios/Classes/InAppWebView/InAppWebView.swift
+++ b/flutter_inappwebview_ios/ios/Classes/InAppWebView/InAppWebView.swift
@@ -1541,7 +1541,7 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
         super.evaluateJavaScript(javaScriptString, completionHandler: completionHandler)
     }
 #else
-    public override func evaluateJavaScript(_ javaScriptString: String, completionHandler: ((Any?, Error?) -> Void)? = nil) {
+    open override func evaluateJavaScript(_ javaScriptString: String, completionHandler: (@MainActor (Any?, (any Error)?) -> Void)? = nil) {
         if let applePayAPIEnabled = settings?.applePayAPIEnabled, applePayAPIEnabled {
             if let completionHandler = completionHandler {
                 completionHandler(nil, nil)
diff --git a/flutter_inappwebview_macos/macos/Classes/InAppWebView/InAppWebView.swift b/flutter_inappwebview_macos/macos/Classes/InAppWebView/InAppWebView.swift
index 425ce3551..e8cc61739 100755
--- a/flutter_inappwebview_macos/macos/Classes/InAppWebView/InAppWebView.swift
+++ b/flutter_inappwebview_macos/macos/Classes/InAppWebView/InAppWebView.swift
@@ -939,7 +939,7 @@ public class InAppWebView: WKWebView, WKUIDelegate,
         super.evaluateJavaScript(javaScriptString, completionHandler: completionHandler)
     }
 #else
-    public override func evaluateJavaScript(_ javaScriptString: String, completionHandler: ((Any?, Error?) -> Void)? = nil) {
+    open override func evaluateJavaScript(_ javaScriptString: String, completionHandler: (@MainActor (Any?, (any Error)?) -> Void)? = nil) {
         if let applePayAPIEnabled = settings?.applePayAPIEnabled, applePayAPIEnabled {
             if let completionHandler = completionHandler {
                 completionHandler(nil, nil)