Strontium is one of those materials that stops you cold the first time you see it in a recipe. You have the Modification Station unlocked, you can see the upgrades you want, and then there it is: a refined radioactive element you have no idea how to make. The good news is that getting Strontium in Subnautica 2 is straightforward once you know the pipeline. You need Celestine, a Processor, and a bit of time spent in the eastern part of the map.
What is Strontium and why do you need it?
Strontium is a refined material described as a "radioactive element used in Radioisotope Thermoelectric Generators (or RTGs) and other nuclear applications." In practical terms, it is a late-game crafting ingredient that unlocks four meaningful upgrades across the Modification Station and Vehicle Fabricator. You cannot find it lying around in the world. Every piece must be crafted.
Processor converts Celestine to Strontium
How do you get Strontium in Subnautica 2?
The recipe is simple: process 2 Celestine at the Processor to produce 1 Strontium. That means if you want to craft everything that requires it, you need a total of 9 Strontium, which works out to 18 Celestine. Stock up before you head back to base.
The Processor needs to be powered, so make sure your base has a reliable energy source running before you start processing. A dead Processor wastes a trip.
Collect Celestine in bulk while you are out scouting. Carrying back 20 or more pieces in a single run saves multiple trips later when you need Strontium for several recipes at once.
Where to find Celestine
Celestine is a silver-blue spiky mineral that appears in the mid-game, past the Graveyard biome heading toward the Alien Base. You need a Sonic Resonator to mine it. If you have not built one yet, check out our guide on finding lead and best farming spots since lead is part of the early resource chain that gets you there.
Celestine is abundant across the eastern portion of the map. Three specific locations worth targeting:
- Southeast of the main Alien Base: A large mountain populated by Needler Fish. Celestine grows heavily on the walls of this structure, and you will also find Creature Enamel here.
- Southeast of the main Axum Turbine: Check the outer walls of the mountain near the Cicada Wreck for solid Celestine deposits.
- Root Garden Biome: Both the northern and southern sections contain Celestine near the Metal Farms.
Celestine grows on eastern mountain walls
Needler Fish patrol the mountain southeast of the Alien Base in numbers. Mine quickly and keep moving rather than stopping to fight them.
What can you craft with Strontium?
Here are all four recipes listed below. Two use the Modification Station and one uses the Vehicle Fabricator.
The Feedback Resonator is an upgraded Sonic Resonator built specifically for destroying armoured viral blooms. If you are pushing into areas with heavy bloom infestation, this is the first thing worth crafting. The Tadpole Haul Chassis adds an extra inventory's worth of carrying capacity to your Tadpole at the cost of speed, which is useful for long resource runs. Strike Armor reduces physical damage from attacks and collisions, while the Cavitation Muffler lowers the Tadpole's sound signature so predators are less likely to lock onto you.
Crafting all four items requires exactly 9 Strontium total, meaning 18 Celestine. If you are only prioritizing one upgrade, the Feedback Resonator is the most useful for progression since viral blooms block access to deeper areas.
Which Strontium upgrade should you prioritize?
After testing these upgrades across multiple runs, the priority order looks like this. The Feedback Resonator comes first because bloom infestations gate content. Without it, you are physically blocked from certain areas. The Tadpole Haul Chassis comes second if you are doing heavy resource farming since the extra carry capacity compounds over multiple trips. Strike Armor and the Cavitation Muffler are quality-of-life improvements that matter more once you are regularly navigating dangerous biomes.
For a broader look at everything you need to gather across the game, the full Subnautica 2 resource guides cover materials from early-game basics through late-game refinement chains. Strontium sits near the top of the survival games crafting curve, but once you have a Celestine farming route dialed in, keeping your supply topped up is straightforward.