No, you do not need the ship Wifi on and it will not take up your internet minutes when you use Spotify downloads. I use this on every cruise and it works perfectly. I create a playlist for every cruise and download much more than I could ever listen to. It's easy to find your downloads but you do need a subscription to Spotify to use this feature. Just don't forget to logoff of the ship internet when you are done surfing/emailing, it will get you every time.