diff --git a/packages/terminal/src/browser/terminal-frontend-contribution.ts b/packages/terminal/src/browser/terminal-frontend-contribution.ts
index d7a7ef7c4c6a1..1b1b4555442ac 100644
--- a/packages/terminal/src/browser/terminal-frontend-contribution.ts
+++ b/packages/terminal/src/browser/terminal-frontend-contribution.ts
@@ -830,7 +830,7 @@ export class TerminalFrontendContribution implements FrontendApplicationContribu
 
     async newTerminal(options: TerminalWidgetOptions): Promise<TerminalWidget> {
         const widget = <TerminalWidget>await this.widgetManager.getOrCreateWidget(TERMINAL_WIDGET_FACTORY_ID, <TerminalWidgetFactoryOptions>{
-            created: new Date().toString(),
+            created: new Date().toISOString(),
             ...options
         });
         return widget;