Subnautica Vehicle Progression Guide: Seamoth, Cyclops and Prawn Suit

Subnautica’s vehicle progression is one of the game’s most satisfying mechanical journeys. You begin swimming alone in a vast ocean, then build a personal submarine, then a massive mobile base, then a powered exosuit that lets you walk on the ocean floor. Each vehicle unlocks new areas of the game and new gameplay possibilities. Understanding the Seamoth, Cyclops, and Prawn Suit progression — what each vehicle does, when to build it, and how to upgrade it — is fundamental to completing Subnautica.

The Seamoth: Your First Submarine

The Seamoth is a small, one-person submarine that dramatically expands your exploration range. It is fast, manoeuvrable, has a small storage compartment, and provides a pressurised environment (oxygen as long as the vehicle is powered). Building it requires a Vehicle Bay in your base and the Seamoth blueprint — obtained from fragments in the Kelp Forest and Grassy Plateau wrecks.

The Seamoth’s key limitation is depth. Without upgrades, it can only dive to 200 metres. Depth upgrade modules (Seamoth Depth Module Mk1, 2, 3) extend this to 900 metres at the highest tier. These modules are crafted at the Vehicle Upgrade Console in your Moonpool. The Seamoth is your primary exploration vehicle for the entire early and mid-game.

Seamoth Upgrades Priority Order

Depth Module Mk1 (extends to 300m) — build immediately after the Seamoth
Sonar — helps detect terrain and creatures in dark biomes
Perimeter Defence System — electric shock deterrent that breaks Reaper Leviathan grabs
Depth Module Mk2 (extends to 500m) — needed for the Lost River approach
Depth Module Mk3 (extends to 900m) — maximum depth for Seamoth, enables reaching all Seamoth-accessible areas
Storage Module — additional inventory space for extended mining and exploration runs

The Cyclops: Your Mobile Base

The Cyclops is the largest vehicle in Subnautica — a full-size submarine with an interior you can walk around in, sleep in, fabricate in, and launch your Seamoth from. It requires three blueprint fragments (from wreck sites in the Mushroom Forest, Sea Treader Path, and Underwater Islands areas), and the materials to build it are substantial: a Cyclops needs significant quantities of Plasteel, Lead, and Enameled Glass.

The Cyclops is your vehicle for the deep-game — it can dock a Seamoth or Prawn Suit internally, allowing you to launch either vehicle on deep dive missions and retrieve them when done. It has its own fire suppression system (necessary, because it can catch fire), a Silent Running mode to reduce creature attraction, and a shield module for emergencies. The Cyclops is where you will spend much of the late game.

The Prawn Suit: Walking the Ocean Floor

The Prawn Suit (Pressure Reactive Armored Waterproof Nano Suit) is a powered exosuit that allows you to walk on the ocean floor, drill mineral deposits, and grapple through terrain. It is your primary vehicle for the endgame — the Lost River and Inactive Lava Zone are best navigated in a Prawn Suit docked to the Cyclops. Its key advantages: it cannot be grabbed by Leviathans (unlike the Seamoth), it can drill into large mineral deposits for resources unavailable otherwise, and its Grappling Arm allows rapid traversal of vertical terrain.

Vehicle Combination Strategy

The ideal late-game exploration approach uses all three vehicles in combination: take the Cyclops to the target area, launch the Prawn Suit for close exploration and mineral drilling, and launch the Seamoth for fast transit in medium-depth sections. Understanding when to use which vehicle makes the difference between efficient deep exploration and frustrating, dangerous mishaps.

Vehicle Videos on RicardoPlays

The RicardoPlays channel documents each major vehicle milestone in Ricardo’s Subnautica series — the first Seamoth launch, the Cyclops build reveal, and the first Prawn Suit walk. These are some of the most satisfying moments in the series and serve as practical demonstrations of each vehicle’s capabilities and limitations. Watch the channel for the full vehicle progression experience.

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Finding Vehicle Fragments: Where to Look

All three vehicles require blueprint fragments scattered across the game world. Knowing where to look saves significant early-game frustration:

Seamoth fragments: Found in the wreckage sites in the Kelp Forest and Grassy Plateau. There are multiple fragment sites — scan 3 fragments to unlock the full blueprint. The Kelp Forest wrecks at medium depth (50-80m) are usually the first ones you will find
Cyclops fragments: The Engine, Bridge, and Hull blueprints are found separately. Engine fragments are in the Mushroom Forest; Bridge fragments are in the Sea Treader Path wrecks; Hull fragments are in the Underwater Islands. All three must be scanned independently to unlock the full Cyclops blueprint
Prawn Suit fragments: Found deep — primarily in the Koppa Mining Site wreck site and in various deep wreckage locations around the Sparse Reef and Sea Treader Path. Prawn Suit fragment collection requires depth capability in the Seamoth (Mk2 or Mk3 depth module)

The scanner room (a base module) dramatically speeds up fragment hunting. Build one near each major search area, deploy Camera Drones, and scan the area from your base. The scanner room highlights all nearby scannable items including vehicle fragments.

Vehicle Power Management

All three vehicles run on internal power cells. Managing power is critical, especially in the deep game:

The Seamoth recharges in Moonpool docking bays at your base, or from a solar-powered base connection. In the field, power cells are the only option — carry spares
The Cyclops uses the Cyclops Engine, which consumes power from its internal reactor. A Nuclear Reactor module or Bioreactor module installed in the Cyclops provides ongoing power generation — essential for extended deep-game missions away from your base
The Prawn Suit uses a separate power cell. It recharges when docked inside the Cyclops

The most sustainable late-game energy setup is a Cyclops with a Nuclear Reactor module, supplemented by a secondary Bioreactor for non-critical power. This gives you effectively unlimited range as long as you have nuclear fuel or organic material.

Prawn Suit Arm Combinations

The Prawn Suit can equip different arm tools in its left and right arm slots. The most useful combinations are:

Drill Arm + Grappling Arm: The standard end-game combination. The Drill Arm mines large mineral deposits that cannot be collected otherwise; the Grappling Arm provides rapid traversal of vertical terrain and allows you to fling yourself across large gaps. This combination is optimal for the Inactive Lava Zone
Torpedo Arm + Grappling Arm: Useful for combat against aggressive creatures in deep biomes. Less essential if you are playing carefully, but provides options
Drill Arm + Propulsion Arm: The Propulsion Arm can grab and throw objects — useful in base building and some puzzle situations, but less generally useful than the Grappling Arm

For the story-critical areas of the game, the Drill Arm + Grappling Arm combination is the recommended setup. Install this before entering the Lost River.

Connecting Vehicle Progression to Story Progression

Each vehicle milestone in Subnautica directly corresponds to a story progression gate:

Building the Seamoth opens the mid-depth biomes and enables reaching the first Alien Structures
Building the Cyclops enables the deep-game approach — reaching the Lost River and the Disease Research Facility
Building the Prawn Suit (with Drill Arm) enables progression through the Inactive Lava Zone and the endgame

If you are stuck on the story, the answer is almost always “build or upgrade a vehicle.” Cross-reference the story progression guide with this vehicle guide to ensure you have the right vehicle for the biome you are trying to reach. The Subnautica hub has guides for every major mechanic if you need more detail on base building, creature survival, or the endgame areas.