Oxygen Not Included: The Aquatic Planet Pack asks a simple question that ONI veterans have spent years trying to avoid: what if the starting planet was wet—not just a little damp, but truly awash with flooded biomes, marine life, and new systems built around existing ONI physics?
This expansion (planet pack) drops your Duplicants into a world beneath the waves, where they’ll either sink… or finally learn to swim for the first time in ONI history. The result is not just a new map skin—it’s a different set of early- and mid-game pressures that force you to rethink pathing, oxygen logistics, heat management, and what “safe expansion” looks like when the next room may be a submerged pocket waiting to equalize into your base.
Swimming Is a Real Skill Now (And It Changes Everything)
The headline feature is a brand-new Duplicant skill: swimming. In practical ONI terms, that means your colony can operate in and around water without every accidental dip turning into a productivity spiral (or a memorial plaque). Training Dupes to move confidently through flooded areas makes the new planet feel playable rather than punitive—while still leaving plenty of room for the series’ trademark slapstick disasters.
Once swimming becomes part of your toolset, you’ll naturally start designing for water instead of treating it purely as a hazard. That doesn’t mean you can ignore it—liquids still obey the same unforgiving rules of pressure, flow, and temperature—but it does mean your colony’s footprint can expand into spaces that used to be “off limits unless you’re desperate.”
Unreal Aquaculture: New Critters, Plants, and Flooded Biomes
The Aquatic Planet Pack leans hard into underwater exploration. You’ll encounter marine biomes filled with new critters, geysers, and bioluminescent flora—ecosystems that offer fresh options for food, materials, and oxygen-adjacent problem solving.
One standout example is a puffed-up fish that drowning Duplicants can use to grab a life-saving breath. That single mechanic is quintessential ONI: it’s part safety net, part emergent-story engine, and part “now you have one more weird dependency to design around.” The expansion also broadens aquatic ranching, encouraging players to treat water-filled spaces as production zones rather than merely plumbing setbacks.
All-New Elements (Including Rubber) Expand Your Build Options
Beyond the new biomes, the pack introduces new elements that feed directly into ONI’s core loops: construction, power, refinement, and industrial scaling. The most immediately practical addition is rubber production, which is used to craft higher-voltage insulated wires and rubber boots—gear that helps keep your workforce functional even when the base is trending from “humid” to “indoor lagoon.”
In ONI, new materials matter because they change what you can safely route, insulate, and automate. Rubber’s presence nudges the mid-game toward sturdier electrical infrastructure and new approaches to expansion in wet, hostile spaces.
Seaworthy Styles: Over 100 New Cosmetics
If you enjoy making your colony look as good as it (occasionally) runs, The Aquatic Planet Pack includes more than 100 cosmetic blueprints in the Supply Closet. Expect nautical paintings, building skins, outfits, Atmo Suit variations, and other themed touches that let you turn your utilitarian disaster factory into something that feels like it belongs on a flooded world.
Sole Survivor: A New Recruitable Mystery Dupe
The pack also teases a narrative wrinkle: the ability to recruit a strangely evolved Duplicant from another colony—someone who’s adapted to life between beaches and abyssal trenches, watching to see whether your base is worth joining. In a game where the story is mostly what happens between systems, a bespoke character like this is a clever way to give the new planet identity and texture without turning ONI into a scripted campaign.
How It Feels on Mac: What to Expect
Mac players who already enjoy ONI’s dense simulation will feel right at home here—the expansion’s appeal is less about flashy spectacle and more about how it changes your planning. Flooded biomes emphasize:
- Pathing and labor efficiency (water slows work unless you build and train around it)
- Oxygen discipline (submerged spaces punish sloppy breathing setups)
- Base sealing and pressure control (one bad dig can turn a project into a flood response)
- Thermal management (liquids move heat in ways that can help—or quietly ruin you)
If your favorite part of Oxygen Not Included is that moment when one new variable forces you to redesign half your base, The Aquatic Planet Pack delivers that feeling continuously—often with your Dupes literally cannonballing into it.
Mac System Requirements
Minimum:
- Not provided by the publisher at time of writing.
Recommended:
- Not provided by the publisher at time of writing.
Bottom Line
The Aquatic Planet Pack is a strong fit for ONI players who want a new “first 100 cycles” puzzle—one defined by submerged terrain, aquatic ranching, and a colony layout that must respect water as a constant presence rather than an occasional leak. It’s more ONI in the best way: new tools, new threats, and new reasons to laugh when someone inevitably pees in the pool.
