Diamonds spawn in specific biomes, and you need the right tools to collect them

Diamonds in Subnautica appear as small blue crystals on the ocean floor in three main biomes: the Crash Zone, the Mushroom Forest, and the Blood Kelp Zone. You cannot pick them up with your bare hands — you need either a Hardness Grappling Hook or a Drill Arm attached to a vehicle like the Prawn Suit or Seamoth. Without one of these tools, the diamonds will remain stuck to the rock and you will waste time trying to collect them.

The easiest diamonds to reach are in the Mushroom Forest, which sits at a moderate depth and does not have aggressive creatures patrolling it. The Crash Zone has more diamonds but also has Reaper Leviathans that will attack you, so you need a vehicle with strong hull integrity and a way to escape quickly. The Blood Kelp Zone is deep and dark, making it harder to navigate, but it has a steady supply if you know where to look.

Key Takeaways

  • Diamonds appear as blue crystals in the Crash Zone, Mushroom Forest, and Blood Kelp Zone, but you cannot collect them without a Hardness Grappling Hook or Drill Arm.
  • The Mushroom Forest is the safest place to farm diamonds because it has no aggressive predators and moderate depth.
  • You need diamonds to craft the Plasteel Ingot, which is required for the Neptune Rocket and several late-game upgrades.
  • A Prawn Suit with a Drill Arm is the fastest way to collect diamonds because the drill mines multiple resources at once.

How to get a Hardness Grappling Hook or Drill Arm

The Hardness Grappling Hook is the first tool you can build. You craft it in a Fabricator using Titanium, Lithium, and a Diamond — which creates a catch-22 if you do not have any diamonds yet. To break this loop, look for diamonds in shallow caves or use the Drill Arm instead, which you can unlock earlier by finding a Prawn Suit fragment.

The Drill Arm is more efficient because it collects diamonds faster and also gathers other resources like Lithium and Gold at the same time. You attach it to a Prawn Suit, which you build in the Mobile Vehicle Bay once you have four Prawn Suit fragments. The fragments are scattered in the Wreck of the Aurora and in the Safe Shallows, so you can start collecting them early in the game.

If you want to use the Grappling Hook instead, you need to find your first diamond without it. Check the Safe Shallows caves and the Kelp Forest — these areas have diamonds in small quantities and are safe enough to explore without a vehicle.

The Mushroom Forest route: safest and most reliable

The Mushroom Forest sits at 200 to 300 meters depth and contains dozens of diamond deposits. The biome has no Leviathan-class creatures, so you can take your time collecting without constant threat. Bring a Seamoth or Prawn Suit with a Drill Arm, and you can collect 10 to 15 diamonds in a single trip.

Navigate to the Mushroom Forest by heading west from the Safe Shallows and descending gradually. You will know you are in the right place when you see the tall, mushroom-shaped rock formations and bioluminescent plants. Diamonds cluster near the larger rock formations, so scan the ground carefully as you move through the biome.

The Crash Zone: more diamonds, higher risk

The Crash Zone is the wreckage of the Aurora, your starting ship. It contains more diamond deposits than any other biome, but Reaper Leviathans patrol the area and will attack your vehicle. You need a Prawn Suit with upgraded hull plating and a Drill Arm to survive here.

Enter the Crash Zone from the south side, where the Reaper patrols less frequently. Stick to the outer edges of the wreckage and collect diamonds quickly. If a Reaper appears, set up your Prawn Suit's jump jets and ascend rapidly — Reapers cannot follow you into shallow water. Do not attempt this route until you have a fully upgraded vehicle.

The Blood Kelp Zone: deep but worth it

The Blood Kelp Zone sits at 400+ meters depth and has a high concentration of diamonds. The darkness and depth make navigation difficult, so bring a vehicle with good lighting and a full power cell. The zone has Ghost Leviathans, which are less aggressive than Reapers but still dangerous if you get too close.

Use your vehicle's lights to scan the seafloor systematically. Diamonds appear in clusters near rock formations, so move slowly and check each area before moving on. Bring extra power cells because the depth drains your vehicle's battery faster.

What diamonds are actually used for

Diamonds are a crafting material for three main things: the Plasteel Ingot, the Hardness Grappling Hook, and the Prawn Suit Drill Arm. The Plasteel Ingot is the most important — you need 10 of them to build the Neptune Rocket, which is how you finish the game. Each Plasteel Ingot requires one Diamond plus Titanium and Lithium, so you need at least 10 diamonds just to complete the endgame.

You also use diamonds for upgrades like the Prawn Suit Thermal Reactor and the Seamoth Depth Module Mark 2. If you plan to explore the deepest parts of the ocean, you will need multiple diamonds for these upgrades.

How many diamonds you actually need

The minimum is 10 diamonds to craft the Plasteel Ingots for the Neptune Rocket. If you want to upgrade your vehicles and craft the Grappling Hook, plan for 15 to 20 diamonds total. Most players find this amount by visiting the Mushroom Forest twice and the Crash Zone once.

Do not worry about running out — diamonds respawn if you leave a biome and return later. You can farm the same location multiple times if you need more.

Frequently Asked Questions

Can I get diamonds without a vehicle?

You can collect a few diamonds from shallow caves in the Safe Shallows and Kelp Forest by hand, but you cannot reach the large deposits without a Seamoth or Prawn Suit. The hand-collected diamonds are enough to craft your first Grappling Hook, which then lets you collect more.

What is the fastest way to farm diamonds?

A Prawn Suit with a Drill Arm in the Mushroom Forest is fastest because the drill collects multiple resources at once and the biome is safe. You can gather 10 diamonds in 15 to 20 minutes without worrying about predators.

Do diamonds respawn after I collect them?

Yes. If you leave a biome and return later, the diamond deposits will be there again. This means you can farm the same location multiple times if you need more diamonds for late-game crafting.

Should I use the Grappling Hook or the Drill Arm?

The Drill Arm is better because it collects diamonds faster and also gathers Lithium and Gold at the same time. The Grappling Hook is useful early on when you do not have a Prawn Suit yet, but you will eventually want the Drill Arm.