Subnautica 2 has been out for less than a day, and yet it's already attracted a massive number of players.

Unknown Worlds Entertainment launched Subnautica 2 on Steam and Xbox Series X|S at 11 AM ET, May 14. There was a ton of interest right out of the gate, and a look at Steam's most-played games shows some eye-watering concurrent player count stats.

It attracted hundreds of thousands of concurrent players on Steam almost immediately, peaking at 467,582. According to Unknown Worlds, combined concurrents on Steam, Epic, and Xbox topped 651,000.

That dwarfs the launches of other hit Steam games this year, like Windrose. Subnautica 2 was the most-wishlisted game on Steam prior to its launch, and it's clear that those wishlists are converting into sales.