If you’ve ever found yourself huffing at how slow your Seamoth moves when you’re hauling rare materials back from the Lost River, you’re not alone. I spent my first three Subnautica playthroughs sticking to the default thruster before I realized how much of a game-changer the Mercury 2 Thruster Subnautica adds to every deep-sea run. It doesn’t just make your vehicle faster – it cuts down on oxygen waste, lets you outrun leviathans with far less stress, and opens up parts of the map you might have skipped because the trip felt too tedious. This guide breaks down everything you need to know to get and use this upgrade, no hidden tricks or missed blueprint locations left out.
How to Unlock the Mercury 2 Thruster in Subnautica
The first step to getting this upgrade is tracking down its three fragments, and you don’t have to venture into super dangerous deep water to find them. Most of the Mercury 2 thruster fragments spawn in wrecks between 100m and 200m depth, with the highest concentration in the two small wrecks just off the northern coast of Mountain Island. You won’t run into any leviathans there, just a few sand sharks that are easy to avoid if you stick close to the wreck walls. If you can’t find all three there, check the wrecks in the northwestern Mushroom Forest, but you’ll need a Seamoth with at least a level 1 hull upgrade to reach those safely.
To craft the Mercury 2 Thruster once you’ve scanned all three fragments, you’ll need the following materials at a modification station:
- 2 Lithium – you can find these easily in the Mushroom Forest or on the sides of Mountain Island cliffs
- 1 Advanced Wiring Kit – made from 2 Wiring Kits, 1 Computer Chip, and 1 Gold
- 3 Titanium Ingots – smelt 12 Titanium in a Fabricator to make these
- 1 Power Cell – keep a spare on hand for swaps on long dives, too
Don’t make the mistake I did my first run, and forget to build a modification station first. You can’t install the thruster upgrade directly from your fabricator – you’ll need to attach it to your Seamoth or Prawn Suit at the modification station next to your vehicle bay. The whole installation process only takes 10 seconds once you have all the parts, so you can get back out exploring right away.
Core Benefits of Fitting the Mercury 2 Thruster to Your Vehicle
On paper, the Mercury 2 Thruster only boosts your vehicle speed by 35%, but that small percentage makes a massive difference in practice. For Seamoth users, it cuts travel time to the Lava Zone by almost half, which means you spend less time sitting around holding the forward button and more time collecting rare resources like kyanite and ion cubes. You’ll also notice far less power waste on short trips between your base and nearby resource hotspots.
One of the biggest underrated perks is improved escape ability when you run into hostile creatures. Reaper Leviathans can only keep up with a default Seamoth for short bursts, but with the Mercury 2 upgrade, you can outrun them before they get close enough to grab you. I tested this myself last playthrough when I stumbled on a Reaper near the Crash Zone, and I didn’t even have to use the perimeter defense system to get away.
For Prawn Suit users, the difference is even more noticeable. Default Prawn Suits move so slowly that many players skip exploring the deeper cave systems of the Inactive Lava Zone entirely, but with the Mercury 2 thruster, you can zip between lava vents to collect kyanite in a fraction of the time. You’ll also be able to outrun Sea Dragon Leviathan fireballs far easier, which is a huge plus if you’re not confident in your Prawn Suit combat skills. The only small downside is that the upgrade uses 10% more power than the default thruster, but that’s negligible if you carry a couple of spare power cells or park near a thermal vent to recharge.
Pro Tips for Using the Mercury 2 Thruster Effectively
First, pair it with a hull reinforcement upgrade first if you haven’t already. If you’re moving faster, you’re far more likely to crash into rock walls or underwater flora when you’re not paying attention, especially if you’re navigating narrow cave systems. The hull reinforcement cuts down on collision damage by 70%, so you don’t accidentally destroy your Seamoth mid-dive. I learned this the hard way when I crashed into a coral tube at full speed early on and lost 70% of my Seamoth’s health in one hit.
Adjust your control settings to match the faster speed if you’re struggling with handling. If you’re playing on PC, turning down your horizontal sensitivity by 15-20% will make it much easier to navigate tight spaces without veering off course. If you’re playing on console, you can adjust your controller deadzone to make the faster handling feel more responsive too. I play on Xbox most of the time, and turning the deadzone down by 10% made it way easier to explore cave systems without crashing.
Use the speed boost strategically to save power and avoid trouble. Tapping the boost button in short bursts when you’re crossing open water is far more efficient than holding it nonstop, and it’ll extend your power cell life by almost 30% on long dives. Another little-known trick: if you pair the Mercury 2 thruster with the Seamoth’s solar charger upgrade, you’ll barely ever have to worry about power drain when you’re exploring areas above 200m depth. The solar charger will top up your power as you move, so the extra power use from the thruster is completely offset during daytime dives.
Common Mercury 2 Thruster Mistakes to Avoid
The most common mistake new players make is trying to install the thruster on their Cyclops. The Mercury 2 Thruster is only compatible with the Seamoth and Prawn Suit, so if you want a faster Cyclops, you’ll need the separate Cyclops engine efficiency and speed upgrades. I’ve seen dozens of players waste hours crafting the Mercury 2 upgrade thinking it’ll work for their Cyclops, so double check your vehicle compatibility before you gather materials.
Another mistake is forgetting to scan all three fragments before heading to the modification station. The fragments are small, easy to miss, and if you only have two scanned, you won’t be able to unlock the blueprint even if you have all the crafting materials. I recommend bringing a scanner room with range upgrades to the Mountain Island wreck area to find the fragments fast, it’ll cut your search time down from an hour to 10 minutes at most.
You also don’t want to make the error of ignoring power levels on long dives. As we mentioned earlier, the thruster uses slightly more power, so if you’re heading to the Lava Zone, bring at least two spare power cells so you don’t get stranded far from your base. I once forgot mine and had to limp all the way back to my base at half speed, because I was scared to go fast and risk destroying the Seamoth entirely. It was a 20 minute trip that should have taken 5, so don’t make that same error.
Finally, don’t skip testing the thruster in shallow water first. If you’re used to the default thruster speed, the Mercury 2 will feel very fast and slippery at first. Spend 10 minutes zooming around the Safe Shallows to get used to the handling before you head into deep, dangerous areas. It’ll save you from crashing into walls or running into creatures you could have easily avoided if you’d taken the time to practice.
At the end of the day, small upgrades make the biggest difference in Subnautica, and this thruster is one of the first I craft in every playthrough now. It doesn’t just make the game feel less grindy – it lets you focus on the fun parts of exploring, instead of wasting time traveling back and forth across the map. If you’ve been sleeping on adding the Mercury 2 Thruster Subnautica has to offer to your vehicle loadout, now’s the perfect time to track down those fragments and craft it for your next dive. You’ll wonder how you ever played without it.
