You can earn Stadium Keys by playing battles on the Map. When a battle offering a Mine Key appears, you’ll see a notification at the top of your screen.

Go to that zone and complete the battle to collect the Mine Key. Try to gather as many as possible while the Stadium event is active (48 hours).

Note: Stadium Keys are valid ONLY for the current Wizard Stadium event and cannot be saved or used in future events. Be sure to use them before the event ends!

Learn more about: How does the new Wizard Stadium work? and Wizard Stadium