Mario Kart Tour available to download, but won't be playable until "around 4 AM ET," requires Nintendo Account

As expected, Mario Kart Tour has gone up for download a few hours before the game actually goes live. You can download the game now, but you won't be able to play until "around 4 AM ET" according to Nintendo. For what it's worth, the in-game maintenance message says maintenance lasts until 3 AM ET, so perhaps things will go live a bit sooner.

Nintendo also notes that the game is going to require you to have a Nintendo Account, so you might as well sign up now while you're waiting for the game to go live.