The Tadpole is the backbone of deep-sea exploration in Subnautica 2, and upgrading it properly makes the difference between cautious surface skimming and confident deep-water runs. There are seven upgrade modules to track down, scattered across the ocean floor, Alterra shipwrecks, and a couple of locations that require some serious navigation. None of them are handed to you.
Before getting into specific locations, one thing worth knowing: most upgrades cluster around the Alien Ruins Research Outpost, roughly 1300m east of your Lifepod. The Scout Ray Chassis is the only exception. Plan your route with that outpost as your hub and you'll save a lot of backtracking.
Grab the Scout Ray Chassis first if you have the resources. The speed boost it gives your Tadpole makes every subsequent upgrade hunt noticeably faster.
Where is the Scout Ray Chassis?
This one sits inside the Tadpole Pens, located in the warm area of the ocean. It's the only upgrade not tied to the Alien Ruins Research Outpost, so grab it early. Head inside the Tadpole Pens, follow the straight path through the facility, and you'll find the Scout Ray waiting in the Moonpool. Scan it with your scanner and the blueprint is yours.
If you haven't unlocked the Tadpole Pens door yet, check out the Tadpole Pens keycode guide for the exact steps to get inside.
Subnautica 2 Guide: All Tadpole Upgrade Locations
Where is the Engine Efficiency upgrade?
Head east from your Lifepod until you reach the Alien Ruins Research Outpost at approximately 1300m. Enter the outpost and turn right. The Engine Efficiency module is right there, no complex navigation required. This is the most straightforward pickup of the bunch.
Where is the Strike Armor upgrade?
From the Research Outpost, set your compass to between 195 and 210 degrees and descend gradually to around 190m depth. Don't take a sharp dive here; a steady descent keeps you on course. The platform holding the Strike Armor upgrade sits roughly 60m from the outpost itself.
Where is the Cavitation Muffler upgrade?
This is the most remote module in the set. From the front of the Research Outpost, head deeper while aiming at roughly 75 degrees east on the compass. You'll pass a structure called the Power Center (look for the distinctive arc shape) and then a large pillar. Keep going.
The screen will take on a greenish tint as you continue, and you'll spot colorful alien plants to your right. Stay left and keep descending toward 350m, then push to about 370m. The Cavitation Muffler sits on a platform at the edge of a cliff on the left side, very close to the early access area boundary. Grab it and head back to the outpost.
The Cavitation Muffler platform is right at the edge of the accessible area in early access. Don't push past it or you'll hit the boundary.
Where is the Photovoltaic Charger upgrade?
From the outpost, aim at 120 degrees on the compass and look for the Blackbox – Iso marker as your navigation reference. Hold a steady depth of 120m and head straight until you reach an Alterra starship wreck. Park your Tadpole outside and enter through the door on the left.
Inside: go straight, turn right, and you'll find a broken door. Repair it, head through, turn left into the next room, then take the door in the left corner. The Photovoltaic Charger module is in that final room, diagonally opposite the dining table where the ISO sits.
Subnautica 2 Guide: All Tadpole Upgrade Locations
Where is the Depth Module Mk. I upgrade?
Back at the front of the Research Outpost, aim at 165 degrees on the compass and follow the Blackbox – Ruby 2 marker. Descend to the bottom layer of the location. There's a gap through some broken rocks; the narrow spot on the left works as an entry point, but leave your Tadpole outside since it won't fit. Inside, you'll find Ruby 2's black box and, right next to a broken-down Tadpole, the Depth Module Mk. I.
How do you unlock the Haul Chassis?
The Haul Chassis requires scanning three separate fragments rather than picking up a single module. Here's where each one is:
- Fragment 1: Right next to the Depth Module Mk. I pickup at the Ruby 2 location.
- Fragment 2: From the Research Outpost, head toward 105 degrees on the compass, pass the dome of the Power Center, and continue straight to another Alterra shipwreck at around 200m depth. The second fragment is on a platform to the left of the wreck.
- Fragment 3: Head past the Angel Comb location (following the root past the alien structures) until you reach an acidic pool. Look left after entering the pool room, past the alien structures, and the final fragment is there.
Scan all three and the Haul Chassis blueprint unlocks.
The Haul Chassis is worth the extra effort if you're doing resource runs. More cargo space means fewer trips back to base.
For broader context on everything the Tadpole can do and how base building connects to your submarine setup, the Subnautica 2 new features overview covers the full picture of what's available in early access. Once you've got your upgrades sorted, the rest of our Subnautica 2 guides have you covered for survival, story progression, and everything in between.