Subnautica 2 has started early access with the kind of launch that turns a popular sequel into a Steam event. Unknown Worlds says the game sold more than 2 million copies in its first 12 hours, after already passing 1 million sales in just one hour. Across PC and Xbox, the game also reached more than 651,000 concurrent players, with Steam making up more than 467,000 of that peak.
The rush was not a surprise, but the speed still stands out. Subnautica 2 had already crossed
5 million Steam wishlists before release, and its first day pushed the series back into the spotlight across Steam’s top sellers list. For an early access game, that gives Unknown Worlds a huge audience from the first build, and a lot of feedback to sort through fast.
The first Subnautica became a survival favorite because it made exploration feel beautiful and dangerous at the same time. Players were not just gathering resources or building bases. They were diving deeper into an ocean that always seemed ready to punish one more bad decision.
That is the feeling Subnautica 2 is trying to bring back, now on a new alien world and with co-op added to the mix. The launch numbers show that players were ready to return, even knowing the game is still in early access and will grow over time.
The early Steam response has also been strong. With more than 18,000 positive Steam reviews soon after launch, with the game sitting at a “Very Positive” user rating while players worked through the first public version.
Subnautica 2 can still be played alone, but the biggest new draw is four-player co-op. Unknown Worlds describes the game as a survival adventure where players can build bases, craft tools, and explore the new ocean world alone or with friends.
That makes this launch feel different from the original. Subnautica built much of its tension around isolation. The sequel now has to keep that sense of danger while letting groups share discoveries, build together, and survive the same threats as a team.
Early access gives Unknown Worlds room to tune that balance in public. With hundreds of thousands of players already diving in, co-op issues, performance problems, progression complaints, and missing quality-of-life features will surface quickly.
Unknown Worlds has shared an early access roadmap that starts with smaller fixes before moving into larger content updates. The first planned update focuses on quality-of-life improvements, while the next one is built around co-op features such as voice chat, emotes, player trading, revives, and better base-building tools.
Later updates are expected to add more biomes, creatures, resources, tools, vehicles, and story content. The studio says the roadmap can change based on feedback, which is important now that the game has launched with such a large player base.
Subnautica 2 reached early access after months of public tension around Unknown Worlds and Krafton, including a legal dispute over studio leadership, release timing, and a major earnout tied to the game’s performance. That drama made the road to launch unusually messy for a survival sequel.
The first 12 hours have shifted attention back to what players came for: a new ocean to explore, strange creatures to survive, bases to build, and a co-op system that will now be tested by one of the biggest early access crowds of the year.
