The free pre-launch tournament is open from 6 p.m. PT on June 1 to 11:59 p.m. PT on June 3.
Nintendo has just announced that they will release a demo of the game on June 1, and also run an online tournament starting the very same day. Currently, there are 15 confirmed characters: Mario, Luigi, Princess Peach, Daisy, Wario, Waluigi, Bowser, Bowser Jr., Yoshi, Donkey Kong, Boo, Toad, Toadette, Rosalina and Chain Chomp. In addition, the title will feature a campaign mode where we will enjoy an adventure that will take us to face some bosses of the series.
Mario Tennis Aces will be available to play early from June 1 to June 3 before it's released on June 22. If you gain enough performance-related points, you can unlock a further five characters, though it's not clear who these are. Nintendo won't say who those characters are yet, but we have a pretty good idea. You'll be able to try Mario Tennis Aces for free before it launches. It's, of course, up to Mario to bail out his brother and complete several tennis-related challenges. Another short clip highlighted the game's single-player Adventure Mode.
So far, the Pre-Launch Online Tournament's timings have only been announced for Europe, with no mention of when the beta will come to the United States and Australia.
"Mario Tennis Aces" was announced by Nintendo during a surprise Direct livestream back in March. Everyone that participates in the event will unlock Mario's iconic blue overalls in the full version of the game.