Just days after launching into Early Access, Unknown Worlds’ highly anticipated underwater survival sequel Subanutica 2 has already become one of the biggest gaming success stories of 2026.

The game reportedly sold more than one million copies within its first hour on sale before quickly climbing past two million copies in less than half a day. By the end of its first five days, sales had surged to roughly four million copies worldwide, generating an estimated $100 million in revenue.

Much of that success came from Steam, where player numbers exploded shortly after launch. Across all platforms, including Xbox Series X|S and Game Pass, concurrent player counts surpassed 650,000, highlighting just how much anticipation surrounded the sequel.

Players have largely praised the game’s expanded co-op functionality, deeper survival systems, and the sense of wonder that made the original Subnautica such a standout experience. Exploring alien oceans alongside friends has proven to be a winning formula, helping the sequel attract both returning fans and newcomers.

“We’re incredibly grateful for the response from players around the world,” said Fernando Melo, Executive Producer of Subnautica 2. “Seeing millions of players dive into this new world during Early Access has been an incredible moment for the team. Community feedback continues to help shape the future of Subnautica 2, and we’re excited to keep building the experience together with our players.”

Unknown Worlds also shared that upcoming updates throughout Early Access will continue incorporating player feedback.