Depth is the ultimate gatekeeper in Subnautica 2. No matter how well-equipped you are, if your vehicle cannot withstand the crushing pressure of the deep ocean, you will never reach the resources, biomes, and story beats hidden below 300 meters. Vehicle depth upgrades are not optional — they are the progression backbone of the entire game. This guide covers every depth upgrade path for every vehicle, the exact material costs per tier, the critical depth milestones you need to hit, and the prerequisites you must satisfy before each upgrade becomes available.
Why Depth Upgrades Matter
Every vehicle in Subnautica 2 has a base crush depth. Crossing this threshold triggers a warning, and continuing deeper causes progressive hull damage that eventually destroys the vehicle in seconds. The Seamoth starts with a 200-meter crush depth. The Prawn Suit begins at 400 meters. Without upgrades, vast portions of the map are permanently inaccessible.
Depth upgrades do more than increase survivability — they unlock entire gameplay loops. Kyanite deposits, thermal vents, Lost River access, Leviathan territories, and late-game blueprint fragments all lie beyond the base crush depths of your starting vehicles. Prioritizing depth upgrades early is the single most impactful decision you can make in your first ten hours of gameplay.
Seamoth Depth Upgrade Path
The Seamoth is your primary exploration vehicle for the first half of the game. It is fast, maneuverable, and has the most upgrade slots of any small vehicle. Its depth upgrade path consists of three distinct modules, each crafted at the Vehicle Upgrade Console inside a Moonpool.
| Upgrade | Max Depth | Materials Required | Unlock Prerequisite |
|---|---|---|---|
| MK1 Depth Module | 300m | 1 Titanium Ingot, 2 Ruby, 1 Wiring Kit | Seamoth constructed; Vehicle Upgrade Console built |
| MK2 Depth Module | 500m | 1 MK1 Module, 3 Nickel Ore, 2 Advanced Wiring Kits | MK1 installed; Fabricator upgraded; 300m+ explored |
| MK3 Depth Module | 900m | 1 MK2 Module, 2 Kyanite, 1 Polyaniline, 1 Enamel Glass | MK2 installed; Lost River entrance discovered |
MK1: The Essential First Step
The MK1 Depth Module should be your first vehicle upgrade priority. Ruby is abundant in the Kelp Forest Caves and the Grassy Plateaus, making the materials easy to gather. The 300-meter limit opens up the Jellyshroom Caves and the deeper Mushroom Forest regions, both of which contain critical early-game resources like Magnetite and Lithium.
Without MK1, you are effectively locked out of approximately 40% of the game's explorable volume. The Seamoth's speed advantage makes it the ideal vehicle for scouting new biomes, and MK1 extends that scouting range dramatically.
Craft the MK1 module before you construct your first Moonpool. You can install the module at any Vehicle Upgrade Console, including ones found in abandoned Degasi bases. This allows you to hit 300 meters immediately after building the Seamoth, without waiting for the full Moonpool resource investment.
MK2: Breaking the Mid-Game Barrier
The MK2 module is where depth upgrades start to demand serious exploration. Nickel Ore only spawns below 350 meters, primarily in the Lost River and Blood Kelp zones. You will need the MK1 module active to safely reach these depths and harvest Nickel without taking hull damage.
Reaching 500 meters unlocks the Inactive Lava Zone entrances, the Deep Grand Reef, and several Alterra wreck sites containing advanced blueprints. The MK2 upgrade is also a prerequisite for the Prawn Suit Drill Arm and several late-game scanner upgrades.
MK3: The Deepest Frontier
The MK3 Depth Module is the final Seamoth upgrade and requires Kyanite — a resource found exclusively in the Inactive Lava Zone and deeper. At 900 meters, the Seamoth can reach almost every biome in the game except the deepest lava chambers. This upgrade effectively turns the Seamoth into an all-terrain scout vehicle capable of accessing end-game content.
The Seamoth cannot survive the Active Lava Zone even with MK3. Temperatures exceed 70°C and pressure exceeds 900 meters in the Active Lava Zone. Do not attempt to enter with a Seamoth — use the Prawn Suit or the Cyclops instead. Losing a fully upgraded Seamoth to lava is one of the most expensive mistakes in the game.
Prawn Suit Depth Upgrade Path
The Prawn Suit is your heavy-duty work vehicle. It starts with a 400-meter crush depth, which is already deeper than the base Seamoth. Its upgrade path is shorter but more resource-intensive, reflecting its role as a late-game vehicle.
| Upgrade | Max Depth | Materials Required | Unlock Prerequisite |
|---|---|---|---|
| MK1 Depth Module | 700m | 1 Plasteel Ingot, 3 Nickel Ore, 2 Ruby, 1 Computer Chip | Prawn Suit constructed; Moonpool with Vehicle Bay |
| MK2 Depth Module | 1300m | 1 MK1 Module, 3 Kyanite, 2 Polyaniline, 1 Synthetic Fiber | MK1 installed; Lava Castle discovered |
Prawn Suit MK1: Expanding Your Reach
The Prawn Suit MK1 is relatively straightforward to acquire. Nickel Ore and Ruby are both harvestable with the Prawn Suit's default arm configuration, and the Plasteel Ingot is a mid-tier crafting component you will likely have already produced for base construction. The 700-meter limit covers the entire Lost River, most of the Inactive Lava Zone, and all primary Kyanite deposits.
The Prawn Suit's jump-jet and grapple arm make it surprisingly mobile in vertical environments, so the MK1 upgrade effectively opens up the entire mid-to-late game resource loop.
Prawn Suit MK2: Maximum Depth
The MK2 module pushes the Prawn Suit to 1300 meters — deep enough to survive the Active Lava Zone and reach the primary Alien Thermal Plant. Kyanite is the bottleneck here, requiring multiple trips to the Inactive Lava Zone with MK1 active. Synthetic Fiber is crafted from Bloodvine samples found in the Blood Kelp Trench.
At 1300 meters, the Prawn Suit becomes the only vehicle capable of exploring the deepest reaches of Planet 4546B. Every end-game location, every final blueprint, and every story conclusion is accessible once this upgrade is installed.
Cyclops Depth Upgrade Path
The Cyclops is your mobile base — a massive submarine that serves as a portable crafting station, storage hub, and vehicle carrier. Its depth upgrade path is the shortest but most expensive in the game.
| Upgrade | Max Depth | Materials Required | Unlock Prerequisite |
|---|---|---|---|
| MK1 Depth Module | 500m | 1 Plasteel Ingot, 3 Ruby, 2 Advanced Wiring Kits | Cyclops constructed; Engine online |
| MK2 Depth Module | 800m | 1 MK1 Module, 3 Nickel Ore, 2 Kyanite, 1 Lead | MK1 installed; 500m+ traveled in Cyclops |
| MK3 Depth Module | 1200m | 1 MK2 Module, 3 Kyanite, 2 Polyaniline, 1 Enamel Glass | MK2 installed; Alien Thermal Plant visited |
Cyclops MK1: Safe Passage
The Cyclops starts with a 200-meter crush depth — far shallower than either the Seamoth or Prawn Suit. This is a deliberate design choice: the Cyclops is intended as a mobile surface base, not a deep explorer. The MK1 upgrade extends this to 500 meters, which is sufficient for transporting the Prawn Suit to Lost River drop points and establishing forward outposts.
Cyclops MK3: The Mobile Fortress
At 1200 meters, the Cyclops can follow the Prawn Suit into the Inactive Lava Zone, serving as a mobile respawn and resupply point. This is invaluable for extended deep expeditions where surface trips are impractical. The MK3 module requires Polyaniline, which is crafted from Deep Shrooms found exclusively below 400 meters, and Enamel Glass, which requires Stalker Teeth — a resource many players overlook.
Do not rush Cyclops depth upgrades. The Cyclops is slow, loud, and attracts Leviathans. In most situations, it is faster and safer to park the Cyclops at a safe depth (300–400 meters) and use the Prawn Suit for deep exploration. Reserve Cyclops MK2 and MK3 for story-critical expeditions where you need onboard crafting and storage at depth.
Depth Milestone Summary
Here is a quick-reference table of the critical depth thresholds and what they unlock:
| Depth | Biome/Content Unlocked | Required Vehicle Upgrade |
|---|---|---|
| 200m | Grassy Plateaus Caves, early wrecks | None (base Seamoth) |
| 300m | Jellyshroom Caves, Magnetite deposits | Seamoth MK1 |
| 400m | Lost River entrance, Blood Kelp Trench | Seamoth MK2 or Prawn Suit base |
| 500m | Deep Grand Reef, Degasi Base 3 | Seamoth MK2 or Cyclops MK1 |
| 700m | Lost River Core, Ghost Tree | Prawn Suit MK1 |
| 900m | Inactive Lava Zone entrance | Seamoth MK3 |
| 1200m | Active Lava Zone, Alien Thermal Plant | Cyclops MK3 |
| 1300m | Primary Lava Castle, end-game story | Prawn Suit MK2 |
Unlock Prerequisites Explained
Many depth upgrades have hidden prerequisites beyond simple material costs. Understanding these triggers helps you plan your progression and avoid wasting time searching for blueprints that are not yet available.
- Biome Discovery: Several upgrades require you to physically enter a biome before the blueprint appears. The MK2 Seamoth upgrade requires entering a biome below 300 meters. The MK3 Prawn Suit requires discovering the Lava Castle.
- Fabricator Tier: Advanced Wiring Kits and Computer Chips require an upgraded Fabricator, which in turn requires finding and scanning the Fabricator upgrade fragment. These fragments are scattered across wrecks and abandoned bases.
- Vehicle Mileage: The Cyclops MK2 requires traveling 500+ meters in the Cyclops. This is cumulative across all sessions and unlocks automatically once the threshold is reached.
- Story Triggers: Some upgrades are gated behind story events. The Prawn Suit MK2 blueprint only becomes available after the Sunbeam event, and the Cyclops MK3 requires visiting the Alien Thermal Plant.
Summary: Prioritize Depth, Explore Everything
Vehicle depth upgrades are the key that unlocks Subnautica 2's deepest secrets. Prioritize the Seamoth MK1 immediately after constructing your first vehicle. Push for the Prawn Suit MK1 as soon as you have Nickel Ore access. Treat Cyclops upgrades as situational luxuries rather than necessities. And always remember: the deeper you go, the more dangerous the ocean becomes — but also, the more rewarding.