Subnautica 2 Tadpole — Depth Module Mk.1/Mk.2 & All Upgrades

What Is the Tadpole?

The Tadpole is the first personal submarine you can build in Subnautica 2 and the primary vehicle for deep-ocean exploration. Compared to swimming by hand, it dramatically increases travel speed, extends safe diving range, and can be equipped with a suite of Mod Station upgrades to handle everything from stealth exploration to heavy cargo runs. Unlocking the Tadpole is one of the most important early-to-mid game milestones — without it, a large portion of mid-to-late game resources and story content remains out of reach.

How to Unlock

The Tadpole blueprint is obtained by scanning Blueprint Fragments found in the ocean. Once the blueprint is unlocked, you also need to build a Vehicle Crafter — a large dedicated station for constructing and repairing vehicles, which itself requires its own set of scanned fragments. Both unlocks are required before you can build your first sub.

Crafting Recipe

Ingredient	Amount	Station	Craft Time
Titanium Ingot	× 2	Vehicle Crafter	10 s
Glass	× 1
System Chip	× 1
Power Cell	× 1

The four ingredients represent the Tadpole's core systems: Titanium Ingot for the pressure hull (smelted from 10× Titanium ore), Glass for the viewport (Quartz + Salt at the Fabricator), System Chip for on-board electronics, and a Power Cell — the primary energy source that determines how long you can drive before needing to recharge.

Depth Modules: Mk. 1 vs Mk. 2

The base Tadpole can only safely reach 250 m before hull pressure begins causing damage. Depth Modules push that ceiling further and are essential for reaching biomes like the Karakorum (Alien Ruins). Both modules are crafted at the Mod Station.

Configuration	Max Safe Depth	Notes
Base Tadpole (no module)	250 m	Default
Depth Module Mk. 1	450 m	Available in Survival mode
Depth Module Mk. 2	800 m	Creative mode only (EA v1)

Depth Module Mk. 1

Adds structural health monitoring systems that raise the Tadpole's safe depth from 250 m to 450 m. This is your first upgrade once you're ready to push deeper. The blueprint databox is found in the Needler Nest, next to Ruby's crashed Tadpole. The main gating material — Celestine — is found in the Karakorum.

Ingredient	Amount	Station
Celestine	× 3	Mod Station
Enameled Glass	× 2
System Chip	× 1

Depth Module Mk. 2

Replaces the Mk. 1's monitoring with adaptive alloy hull reinforcement, pushing the ceiling to 800 m. Important: Mk. 2 does not stack — one module gives the full benefit. Note: as of Early Access v1 the Mk. 2 blueprint is only obtainable in Creative mode; it is not yet available in Survival.

Ingredient	Amount	Station
Dedicated Core	× 2	Mod Station
Troilite	× 2
Mangalloy Ingot	× 2

The Mangalloy Ingot is the hardest ingredient to obtain — it requires Atacamite, a copper chloride mineral found only in the Karakorum at 100–400m. Plan your Karakorum runs to collect Atacamite in bulk so you don't have to make multiple trips.

Tadpole Pens (Story Location)

The Tadpole Pens is a mid-game story facility about 675 m east of the Lifepod at around 150 m depth, situated near hot caves and volcanic vents. NOA directs you there as part of the main quest.

The "Keycode" — How It Actually Works

There is no numeric code to type in manually. The access key was held by a colonist named Zip, whose black box is in a Hot Cave 200–300 m southwest of the facility at 310 m depth. Interact with Zip's Black Box and the code saves automatically to your PDA — return to the locked door, press the button, and it opens.

Inside the Tadpole Pens you'll find the Scout Ray Chassis blueprint, the Moonpool Recipe Data Card, and the NOA terminal that advances the main story.

Chassis Options

The Tadpole supports dockable chassis that change how it performs. All are built at the Vehicle Crafter and are compatible with the Tadpole Dock.

Chassis	Ingredients	Purpose
Haul Chassis	Titanium Ingot ×4 · Strontium ×3 · Enameled Glass ×3 · Dedicated Core ×1	Dramatically expands cargo and passenger capacity at the cost of speed — best for resource farming runs
Scout Ray Chassis	Plasteel Ingot ×2 · Advanced Wiring Kit ×1 · Dedicated Core ×1 · Strong Acid ×1	Enhances acceleration, top speed, and turning — built for fast exploration and covering distance
Seafrog Chassis	Not yet available in Early Access — recipe coming in a future update

Mod Station Upgrades

Beyond depth modules, the Mod Station offers several upgrades that change how the Tadpole handles day-to-day. Stack the right combination for your play style.

Upgrade	Ingredients	Effect
Engine Efficiency	—	Reduces power consumption by 20% per module. Stackable up to 4× for a maximum 80% reduction — run almost indefinitely with a full stack
Cavitation Muffler	Titanium ×3 · Strontium ×2	Reduces Tadpole noise output, making it less likely to attract creature aggression during exploration
Photovoltaic Charger	Copper Ingot ×1 · Strong Acid ×1 · Troilite ×1	Solar-powered recharge for the Power Cell. Only functions in shallow water during daytime — park and wait
Echo Location	Quartz ×3 · Mild Acid ×1 · Atacamite ×1	Mid-to-late game upgrade unlocked through story progression

Tadpole Dock

The Tadpole Dock is the base structure that recharges your submarine. Park the Tadpole inside while your base is powered and the Power Cell will recharge automatically — no manual swapping needed. Built with the Habitat Builder.

Ingredient	Amount	Station
Titanium Ingot	× 2	Habitat Builder
Silver Ingot	× 1
Copper Wire	× 2

Tips

• Build Depth Module Mk. 1 as your first upgrade priority. You can't reach Karakorum without it, and Karakorum is where most mid-game materials come from.
• Install the Cavitation Muffler before entering Karakorum — the Bullethead and other predators are more aggressive there, and a quieter sub means fewer forced detours.
• Stack up to four Engine Efficiency modules for long-range runs. At 80% power reduction your Tadpole can cover enormous distances without returning to base.
• Gather Atacamite in bulk during your first Karakorum descent — it's the bottleneck for both Mk. 2 and the Echo Location upgrade.
• The Photovoltaic Charger is a supplement, not a replacement for the Dock — it only charges in shallow, sunlit water. Use it for daytime surface recharges between dives.
• Mk. 2 does not stack. Craft exactly one — any more is wasted materials.

Frequently Asked Questions