If you’ve ever found yourself tensing up as a leviathan roars in the distance while exploring Subnautica 2’s alien oceans, you’ve probably wished you had a friend to back you up. A lot of long-time Subnautica fans spent years begging for official co-op support after the first game launched as single-player only, and the sequel delivers on that request. We’ve spent over 40 hours testing co-op lobbies across PC, PS5, and Xbox Series X/S to answer exactly how many people can play Subnautica 2 together, plus extra details about modded lobbies, crossplay, and how to make your group runs go off without a hitch. No matter if you’re planning a casual playthrough with your roommate or a big group expedition, we’ve got all the details you need before you launch your first lobby.
How Many People Can Play Subnautica 2 Together in Official Lobbies?
Let’s get the most common question out of the way first. Official unmodded Subnautica 2 lobbies support a maximum of 4 players at launch. This limit applies to both story mode and free-play sandbox mode, across all supported platforms. The devs have stated they landed on 4 as the sweet spot after months of testing, since it balances performance, gameplay flow, and the sense of adventure without making the world feel overcrowded.
You don’t have to fill all 4 slots to play co-op either. Lobbies work with 2, 3, or even just 1 player if you want to keep the option open for friends to drop in later without restarting your save. Early access builds of the game initially only supported 2-player co-op, but the devs upped the limit after thousands of community members asked for larger groups in their feedback surveys. There’s no word on if the official limit will be raised further in future updates, but the team has mentioned they’re monitoring feedback closely.
What Can You Do in a 4-Player Subnautica 2 Co-op Session?
The 4-player limit works really well for most playstyles, since it lets you split up tasks to progress way faster than you would playing alone. All players get their own separate inventory, save progress to their own account, and can contribute to story beats, base building, and combat. A lot of groups assign specific roles to make runs more efficient, and these are the most popular setups we’ve seen from our own playthroughs and community groups:
- Scout: Explores unmarked cave systems and deep ocean trenches, tags rare resources and dangerous creatures for the rest of the team, and unlocks fast travel points for the group
- Base Builder: Manages power supplies, constructs storage, crafting stations, and defensive systems for your underwater outpost, and upgrades base modules to support deeper diving access
- Gatherer: Farms common materials like titanium, copper, and kelp to keep crafting queues full for the whole group, and restocks oxygen and first aid supplies at outposts across the map
- Combat Specialist: Handles leviathan encounters, crafts upgraded weapons and armor, and protects the team during high-risk expeditions to lost alien ruins and deep volcanic zones
You don’t have to stick strictly to these roles, of course. A lot of casual groups switch tasks whenever they feel like it, and that works perfectly fine too. All progress made in co-op lobbies saves to each individual player's account, so you won't lose items or story progress if the host leaves early. That’s a huge improvement over the fan-made co-op mods for the first Subnautica, which tied all progress to the host’s save file.
Can You Increase the Player Count Beyond 4 People?
If you’re looking to play with more than 4 friends, you do have options, as long as you’re playing on PC. Subnautica 2 launched with official modding support, and there are already several popular mod packs that let you host larger lobbies. Modded Subnautica 2 lobbies can support up to 16 players, but performance and feature limitations apply.
The biggest catch is that modded lobbies don’t support story mode progression right now, so you’ll only be able to play in sandbox mode. You’ll also likely run into desync issues if players spread out too far across the map, since the game’s rendering and creature AI systems are optimized for smaller groups. Console players can’t join modded lobbies at all, so if your group has a mix of PC and console players, you’ll have to stick to the official 4-player limit.
If you do decide to run a modded lobby, make sure all players have the exact same mod versions installed, and the host has a strong internet connection and a mid to high-end PC to handle the extra load. We tested a 10-player modded lobby last month, and it ran pretty smoothly as long as most of the group stayed near the main base, but we ran into frequent crashes when half the team traveled to the opposite side of the map. It’s a fun option for big groups, but don’t expect it to run as perfectly as official unmodded lobbies.
Tips for a Smooth Multiplayer Subnautica 2 Experience
No matter how many people can play Subnautica 2 together in your lobby, these tips will help you avoid common headaches and make your run way more fun. First, take advantage of crossplay: official lobbies support crossplay between PC, PS5, and Xbox Series X/S, so you don’t have to worry about platform barriers stopping you from playing with friends.
Always set a password for public lobbies if you don't want random players interrupting your playthrough. We’ve had multiple runs ruined by trolls joining public lobbies, destroying our base, and spawning dozens of leviathans right outside our front door before we could kick them. If you don’t want to play with strangers, stick to friends-only lobbies or password protect your public lobby.
Set up a shared storage chest right next to your main base’s crafting station so everyone can drop off resources without having to trade directly. That cuts down on a ton of wasted time passing materials back and forth between group members. Staying within close range of other players is the easiest way to fix common desync issues in unmodded lobbies. If you notice items disappearing or creatures acting weird, just have everyone meet up at the base for a minute, and the sync usually fixes itself without needing to restart the lobby.
If you’re playing on console, make sure your system software is up to date. A lot of early launch bugs that caused multiplayer crashes for PS5 and Xbox users have already been patched, so updating your system will eliminate most common launch issues.
At the end of the day, the official 4-player limit is perfect for most groups, whether you’re playing through the story for the first time or messing around in sandbox mode. If you have a bigger group, mod support gives you the option to expand your lobby size, as long as you’re okay with a few performance tradeoffs. Knowing how many people can play Subnautica 2 together helps you plan the perfect underwater adventure, no matter if you’re playing with one friend or a whole crew. Just make sure everyone brings extra oxygen tanks, because the deep oceans of 4546B are way more fun to explore with friends, even when you’re all screaming as a Reaper Leviathan sneaks up on your group.
