Subnautica 2 Tadpole Upgrades & Modules: Complete Customization Guide

Building the Tadpole is the milestone. Upgrading it is the game. A stock Tadpole gets you around, but a modded one lets you actually survive the deep zones, haul real cargo loads, and reach areas that would kill you otherwise.

Here’s what you can install, where to get the blueprints, and which upgrades matter most for each chassis type.

How Tadpole Upgrades Work

The Tadpole has module slots that accept different upgrades. Think of them like equipment slots on an RPG character — each slot takes one module, and modules provide passive bonuses or active abilities.

You install modules at your base’s Vehicle Upgrade Console (or equivalent station). Dock your Tadpole, open the upgrade interface, and slot modules in. They take effect immediately.

The number of available slots depends on your chassis:

Haul: More utility/storage module slots
Seafrog: More durability/terrain module slots
ScoutRay: More speed/efficiency module slots

Each chassis favors its specialty, but all three accept the core universal upgrades.

Universal Upgrades (All Chassis)

These modules work on any Tadpole regardless of chassis type.

Depth Module MK1

What it does: Increases maximum dive depth Why it matters: The stock Tadpole has a depth limit. Go past it and the hull takes crush damage. This module pushes that limit deeper.

Build this first. Before storage mods, before efficiency mods, before anything else. Depth access is the gateway to every mid-and-late-game area. Without it, half the map is off limits.

Depth Module MK2

What it does: Further increases maximum dive depth Materials: More advanced than MK1 — expect rare materials

The MK2 lets you reach the deepest biomes on Zezura including the Abyss Edge. You’ll need materials from the mid-game zones to craft it, so treat it as a natural progression rather than something to rush.

Power Efficiency Module

What it does: Reduces power consumption while driving Why it matters: Longer trips, fewer recharges

The Tadpole runs on a Power Cell. Drain it and you’re swimming home. The efficiency module stretches your cell’s life, letting you explore further before needing to dock and recharge. Pairs well with the ScoutRay chassis, which burns more power at high speed.

Hull Reinforcement Module

What it does: Reduces collision and fauna damage Why it matters: Getting bumped by a big creature at 80m depth can ruin your day

This is defensive. It won’t make you invincible, but it gives you a margin of error when fauna rams you or you clip a rock wall at speed. More relevant for ScoutRay pilots who are moving fast through unfamiliar terrain.

Sonar Module

What it does: Active sonar pulse that maps nearby terrain Why it matters: Deep water is dark. Sonar shows you the layout

Send a ping, see the terrain around you light up for a few seconds. Indispensable in cave systems, deep trenches, and the Abyss Edge where visibility drops to nothing. The pulse has a cooldown and draws power, so use it deliberately.

Haul Chassis Upgrades

The Haul chassis is built for cargo. Its unique upgrades lean into that.

Extra Storage Module

What it does: Adds more inventory slots to the Tadpole Why it matters: The Haul already has more storage than the other chassis. This module pushes it further.

If you’re running supply routes between a mining outpost and your main base, stack these. Two Extra Storage modules turn the Haul into a freight train. Fill up at the Old Habitat caves, drive home, dump everything, repeat.

Resource Scanner Module

What it does: Highlights gatherable resources in your HUD while driving Why it matters: No more stopping to look around for Limestone nodes

This module is underrated. Instead of parking the Tadpole and swimming around scanning rocks, you drive through an area and the HUD marks resource locations. Faster gathering with less downtime.

Seafrog Chassis Upgrades

The Seafrog’s walker mode gets its own set of upgrades.

Drill Arm Module

What it does: Replaces one arm with a mining drill Why it matters: Direct resource extraction from large deposits

Some mineral deposits are too big to pick up by hand. The Drill Arm lets you mine them directly from your Seafrog. Walk up to a large Titanium outcrop, drill it, and the materials go straight into your inventory. This is how you gather rare, heavy resources efficiently in the mid game.

Grapple Arm Module

What it does: Fires a grappling hook that pulls you toward anchor points Why it matters: Vertical mobility for a walking vehicle

The Seafrog walks, but it doesn’t climb well. The Grapple Arm fixes that. Fire it at a cliff face, reel yourself up, and access elevated areas that would otherwise require leaving the vehicle. Also useful for pulling yourself out of holes. You will get stuck in holes.

Jump Jet Module

What it does: Short thruster burst for jumping Why it matters: Gaps, obstacles, and the occasional quick dodge

Walking means you can’t simply swim over obstacles. The Jump Jet gives the Seafrog a short vertical boost — not full flight, but enough to clear low walls, hop across gaps, and get out of tight spots. Combines well with the Grapple Arm for full 3D traversal.

ScoutRay Chassis Upgrades

Speed is the ScoutRay’s identity, and its upgrades double down.

Afterburner Module

What it does: Temporary speed boost on activation Why it matters: Escape dangerous fauna or sprint to a distant location

Press the activation key and the ScoutRay surges forward at increased speed for a few seconds. Burns extra power during the boost but can save your life when a leviathan-class creature locks onto you. Also useful for closing long distances when you’ve already spotted your destination.

Stealth Module

What it does: Reduces your detection radius Why it matters: Aggressive fauna won’t notice you as easily

Some biomes have creatures that track movement and sound. The Stealth Module makes your ScoutRay quieter and harder to detect. You can pass through dangerous territory without triggering every predator in the area. Particularly useful in the deep zones where the fauna gets serious.

Streamlining Module

What it does: Improves base speed and turning radius Why it matters: A faster, more responsive ScoutRay

This is a passive buff to your bread-and-butter performance. Faster cruising speed, tighter turns, better handling. Not flashy like the Afterburner, but it compounds over every minute you spend driving. Install it and you’ll feel the difference immediately.

Upgrade Priority Order

Not all upgrades are equal. Here’s the order I’d install them:

Any Chassis

Depth Module MK1 — Access to new areas is always priority one
Power Efficiency Module — Longer range means more exploration per trip
Depth Module MK2 — Full map access
Hull Reinforcement — Insurance against deep-water threats

Haul Specific

Extra Storage Module
Resource Scanner Module

Seafrog Specific

Drill Arm Module
Grapple Arm Module
Jump Jet Module

ScoutRay Specific

Streamlining Module
Stealth Module
Afterburner Module

Where to Find Upgrade Blueprints

Most Tadpole upgrade blueprints come from scanning fragments found at wreck sites and points of interest across Zezura.

Cicada Wreck — Multiple upgrade fragments scattered throughout the wreck structure. Scan everything metallic.

Colonist Bunker — Some upgrade fragments near the bunker interior.

Deep wrecks — Later-game sites have advanced module fragments (MK2 depth, specialty modules).

Data boxes — Sealed containers at various locations sometimes contain complete blueprints without needing fragments.

Scan aggressively. Every time you visit a new location, scan every scannable object. Fragments look like broken pieces of equipment — they glow slightly and your Scanner will indicate them. Many players miss upgrade fragments because they swim past without scanning.

Co-Op Module Considerations

In multiplayer, coordinate your Tadpole builds:

One Haul with max storage for group supply runs
One ScoutRay with Stealth + Streamlining for scouting new areas
One Seafrog with Drill + Grapple for resource extraction

Three specialized vehicles cover every need the group has. If you have a fourth player, a second ScoutRay for long-range exploration is the best call.

Don’t all build the same chassis with the same modules. Redundancy in co-op is wasted resources.

Maintenance and Power

Upgraded Tadpoles draw more power. Each module adds a small baseline drain to your Power Cell. A stock Tadpole might last 15 minutes of continuous driving. A fully modded one might last 10.

Keep your base’s vehicle charging station operational. Dock, charge, go. If you’re running long-distance missions, carry a spare Power Cell. Swapping cells in the field is faster than limping home on empty.