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Watch trailer on Steam ↗Sub Optimal Co.
It's A Sidegame · Published by It's A Sidegame
Mixed — 69% positive (13 reviews) · 30 achievements
Last updated 28 Sept 2026
It's simple. Operate your submarine through challenging tight cave systems to collect the target, while not scratching the cave walls under suboptimal conditions. Navigate carefully and consider every move in this slow pace, athmospheric, multiplayer, submarine simulation-lite.
£3.39
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Price history
Indie, Simulation, Casual · 2026 · More under £5 games
Explore underwater caves and gather targets in Sub Optimal Co., a slow-paced, atmospheric submarine simulation from It's A Sidegame. Navigate with precision to avoid damaging the walls in this casual indie game.
About this game
Invite up to five friends and operate your submarine. Together or alone.
Navigate carefully and consider every move while you progress through one of 20 challenging and unique cave systems in this slow pace, atmospheric diving experience. Reach the target location without crushing your submarine into the walls by operating your cameras, sonar and the submarine's movement. Together or alone. While you can operate the submarine all by yourself - It’s way more effective to have a few helping hands on board. So hire your friends who are up for a claustrophobic dive experience.
It's simple. Operate your submarine through challenging tight cave systems to collect the target, while not scratching the cave walls.
You will be spending 95% in the submarine. You (and your friends) can freely move within it and by operating the submarine's consoles, you can move and navigate your submarine. Dive through challenging cave systems by turning, tilting, rotating and adjusting movement speed, without touching the walls.
If your submarine touches the walls too often, it will sink and the dive failed. The challenge here is that you only have limited tools to see or hear your location within the cave. There is always a target at the end of the cave that you need to reach and return to your base with.
With every new launch or restart of the game, one of 20 caves will be chosen randomly for you to play (more to come). Think of it as some kind of hot-wire mechanic. In a sub. In a cave.
A charming "I am not an submarine expert but I want to maneuver a submarine with my friends but without the torpedo and war stuff going on but only for around one hour per dive" experience.
As you progress further with a successful mission-line, enjoy new ranks, new uniforms, some beards, and some new cups for your character.
This project was designed to be a slow pace, multiplayer experience to play with friends while chatting in your favorite voice-chat. You can even play this game with mouse only, so you got one free hand for your favorite cup of tee, or coffee.
Important to notice:
- "Sub Optimal Co." uses peer-to-peer connection.
- No bots or NPCs can be added to the party.
It‘s a small game. It‘s a simple game. It‘s A Sidegame.
System Requirements
Will my PC run this? →Minimum
- Requires a 64-bit processor and operating system
- OS: Windows 10
- Processor: Intel Core i7-4790K | AMD Ryzen 5 1500X
- Memory: 12 GB RAM
- Graphics: NVIDIA GeForce GTX 1050 Ti | AMD Radeon RX 470
- DirectX: Version 12
- Network: Broadband Internet connection
- Storage: 2 GB available space
Recommended
- Requires a 64-bit processor and operating system
- OS: Windows 10
- Processor: Intel Core i7-9700K | AMD Ryzen 7 3700X
- Memory: 16 GB RAM
- Graphics: NVIDIA GeForce RTX 3060 | AMD Radeon RX 7800XT
- DirectX: Version 12
- Network: Broadband Internet connection
- Storage: 2 GB available space
Supported Languages
Latest news
Patch NotesOfficial
PATCH 1.0.2
Hi all, this patch provides a new information screen to help choosing a cave for your dive, along with some bug and translation fixes. 1.0.2 - Qualitiy-Of-Dive Improvements: Technical Stuff: - Fixed a bug where a player is kicked back to the main menu after finishing a dive - Corrected the final sequence brasilian translation Gameplay Stuff: New Cave Information ScreenThe choosen cave is now displayed on a dedicated overview panel in the HQ-room and the SR-room. It gives you a quick oversight with some specifics like duration, difficulty and other mentionable things. It is here to help divers choose a fitting cave for their play session. I know it's been a while since the last update, sry for that. As always, I hope you enjoy those additions. Let me know what you think or wish for in the discord, instagram or here in the comments. Have a nice dive & greetings, DevRead full article on Community Announcements (Campbell)Patch NotesOfficial
PATCH 1.0.0.6
Hi all, this patch provides some new features along with some bug fixes. Hope you enjoy. 1.0.0.6 Qualitiy-Of-Dive Improvements: Technical Stuff: - Fixed a lot of minor collision bugs - Fixed some UI stuff Gameplay Stuff: New Lobby System You can now open and close a lobby for everyone via the "friend-invite" section in the ESC menu. It allows for a lobby name and an optional password. Everybody can than find those lobbys in the title-screen in the "search lobby" section. This way you don't need to be connected via steam friend list and you can play with randoms. Localisation Everything relevant is now translated into english, brazilian-portuguese and german. Language can be changed in the main menu. New Hats We got two new hats from our discord-server wishlist. If you want to see your favorite headgear in this game, feel free to drop it in the discord channel. Inverted Mouse You can now choose if you want to have inverted controls for the mouse. Of course you can choose the axes separately. Zoomed View "Shift" now squeezes your eyes and zoomes your view. Very helpfull to look for details or look suspicious. The zoom factor can also be set individual in the settings in the ESC menu, as well as the key mapping. As always, I hope you enjoy those additions. Let me know what you think or wish for in the discord, or here. Greetings, DevRead full article on Community Announcements (Campbell)Patch NotesOfficial
Patch 1.0.0.5.5
Just a small patch to repair some annoying bugs and some typos. "Collision clipping" - bug: Should now almost be impossible for the cave to clip through the submarine walls. "Help, I am stuck in the periscope" - bug: Nobody should now be traped in the periscope view. Your typical typos: Fixed some info panel typos and the sonar C-section typos Content patch coming soon. Have a nice dive, DevRead full article on Community Announcements (Campbell)Patch NotesOfficial
PATCH 1.0.0.5
Hi all, this patch is updating the submarine and provides some new features along with some bug fixes. Hope you enjoy. 1.0.0.5 Qualitiy-Of-Dive Improvements: Technical Stuff: - Fixed "push down" and "ballast tank down" bug. The sub should now be stable when operating those buttons. - Fixed "accidental cofffee consumtion" when in the esc-menu. Gameplay Stuff: Remote Camera Access Everywhere You can now operate the camera remote from everywhere - so it has becoma a "real" remote now, finally. Persicope Viewport Additions If operating the periscope, you now got additional cameras available. We got one camera in the front, the back, each side and one on the downside of the submarine. This provides more visual options for navigating the tight, mean, tilted sections of the caves. VoIP And Text Chat Actually pretty standard for a multiplayer focused game aye? And now available in S.O.C. too. Not the most polished option but we now got push-to-talk for the walkie talkies and a textchat. Status Screen Update Time All numbers on the status screen will now update in realtime instead of once every few seconds. Localisation Some may already noticed. The product page is now also translated into brasilian portuguese and german. The localisaton into these two languages is in progress for the ingame text and the manual as well. It just needs some time and I hope to deliver that option with 1.0.0.6 That's it for now. Let me know what you think and feel free to join the Discord or Instagram. Links below. As always, hope you like that and let me know what you think in the comments. Thx to everyone for diving and have a nice day, DevRead full article on Community Announcements (Campbell)Patch NotesOfficial
PATCH 1.0.0.4
Hi all, this patch is updating the submarine and provides some new toys. Hope you enjoy. 1.0.0.4 Qualitiy-Of-Dive improvements: Technical stuff: - Target Collection, Funny Valves & Performance - Fixed damaged valves pointing in funny directions (just cosmetic issue). - Some minor performance improvements and back up stuff. Nothing you should notice during gameplay. Gameplay stuff: - Submarine Typ II - Periscope - Ballast Tanks - New Layout The engineers improved a lot of the submarines layout. So much that it resulted in a new type. You will now find a new bridge, rudder and engine section. Along with this we got new toys on board. A periscope to better understand your surroundings. Ballast tanks for going down or up without constantly pressing the "push" buttons (use them carefully, as they are not effected by the STOP button). And some emergency rudders in the front and back, in case you got traped and don't want to use the sub-port. The Cofffee is now located at the bridge and we got a little more space in every section. A huge thanks to the discord on this. I think it is a way better submarine now than ever before. - Save & Load The way this works is the following: Once the submarine is closed, everyone is able to save the current dive situation with cave, sub-health and sub-position. Loading is exclusive to the host of a session. This way it is possible to return with more or less players and a new set up to a savegame, as the loading takes place after the invite. So feel free to save a difficult situation and come back later with more people to show that cave who is in charge here. - More Sexy ESC Menu Still not the most beautiful, it is now improved with numbers to the sliders. You can type your values for FOV, sound and brightness now. We now also got some icons for cups and hats and stuff. - Manual I created a manual for everyone who wants to have some insights of the games mechanics. It can be found on the right side of the steam product page. Let me know ...Read full article on Community Announcements (Campbell)
