The darkness of the depths is something all gamers will have to adjust to in Subnautica: Below Zero, especially if they want to collect some of the rarest resources. Many of the more desirable crafting components, like the much sought-after Gel Sack, can be found with far more frequency the deeper one dives.

There are a ton of biomes, known as Underwater Caves, that are a bit trickier to find and are usually only accessible from Underwater Biomes, however, these nooks, crannies, and full-on caverns are definitely worth checking out for the undersea bounties they hold.

Arctic Kelp Caves

Murky and easy to get lost in, the Arctic Kelp Caves can be found via cave entrances near the seafloor of Arctic Kelp Forests. Within, players will find lots of Sea Monkey nests, useful fragments, and Kelp Root Pustules above all else. Thankfully, there are also Oxygen Plants, which can be a lifesaver if the player gets turned around and needs a few more seconds to regain their bearings in this maze of giant roots.

Arctic Kelp Caves Points Of Interest

  • Array Module Obelisk Water Analysis Station

Arctic Kelp Caves Databank PDA Entries

  • Alterra Misplaces 1km Capital Ship Aurora

Arctic Kelp Caves Plants

  • Kelp Root Oxygen Plant Radiant Sieve Coral Sulfur Plant

Arctic Kelp Caves Creatures

  • Crashfish Hoopfish Sea Monkey Spinner Fish

Arctic Kelp Caves Fragments

  • Laser Cutter Fragments Mobile Vehicle Bay Fragments Propulsion Cannon Fragment Seaglide Fragment

Arctic Kelp Caves Resources

  • Calaverite Outcrop Copper Ore Crashfish Egg Crystalline Sulfur Gold Ion Cube Limestone Outcrop Quartz Root Globule Salt Deposit Sea Monkey Egg Silver Ore Titanium

Crystal Caves

In the depths, there is great beauty to behold, but the Crystal Caves are not a place to linger and admire the natural radiance of its purple gem-like formations.

There are multiple Shadow Leviathan prowling these waters, which can make exploring the three sub-biomes of this area, the Main Crystal Caves, Crystal Castle, and Crystal Cave Fissure, far more dangerous than most places. However, there is definitely enough buried treasure to make this danger worth the trip, especially if one seeks to upgrade their Prawn Suit’s arms.

Main Crystal Caves Points Of Interest

  • The Crystal Castle sub-biome

Main Crystal Caves Databank PDA Entries

  • None

Main Crystal Caves Plants

  • Blooming Raindrops Jade Membrane Reaper’s Wineglass Ribbon Plant

Main Crystal Caves Creatures

  • Bladderfish Feather Fish (Red) Rockgrub Rock Puncher Shadow Leviathan Triops

Main Crystal Caves Fragments

  • Prawn Suit Propulsion Cannon Fragment Prawn Suit Torpedo Arm Fragment

Main Crystal Caves Resources

  • Argentite Outcrop Calaverite Outcrop Copper Ore Diamond Galena Outcrop Gold Kyanite Large Copper Deposits Large Quartz Deposits Large Silver Deposits Large Titanium Deposits Lead Limestone Outcrop Lithium Magnetite Nickel Ore Quartz Ribbon Plant Rock Ruby Silver Ore Titanium Uraninite Crystal

Crystal Castle Points Of Interest

Crystal Castle Databank PDA Entries

Crystal Castle Plants

  • Sulfur Plant

Crystal Castle Creatures

  • Crashfish Triops

Crystal Castle Fragments

Crystal Castle Resources

  • Crashfish Egg Crystalline Sulfur Diamond Kyanite

Crystal Caves Fissure Points Of Interest

Crystal Caves Fissure Databank PDA Entries

Crystal Caves Fissure Plants

  • Jade Membrane Polycage

Crystal Caves Fissure Creatures

Crystal Caves Fissure Fragments

Crystal Caves Fissure Resources

  • Calaverite Outcrop Gold Large Gold Deposits Large Kyanite Deposits Large Silver Deposits Magnetite Nickel Ore Rockpuncher Egg Titanium

Deep Lilypads Cave

Found by traveling down from the Lilypad Islands biome, this network of crevices is narrow and awkward to traverse in some places, though is well-lit enough for players to not get lost quite as easily as in other Underwater Caves. The glowing plants that illuminate the surroundings are also a target for traveling here, as these Grand Cotton Anemones produce eggs useful for advanced fabrication.

Deep Lilypads Cave Points Of Interest

  • Deep Lilypads Cave Cache

Deep Lilypads Cave Databank PDA Entries

Deep Lilypads Cave Plants

  • Deep Lily Pads Flower Grand Cotton Anemone Green Ternion Hanging Plant Lilypad Loop Plant Oxygen Plant Young Cotton Anemone

Deep Lilypads Cave Creatures

  • Brown Spikey Trap Discus Fish Lily Paddler Spinefish Spinnerfish Squidshark Triops

Deep Lilypads Cave Fragments

Deep Lilypads Cave Resources

  • Argentite Outcrop Calaverite Outcrop Flowering Spore Gold Large Gold Deposit Large Quartz Deposit Large Titanium Deposit Magnetite Nickel Ore Quartz Ruby Silver Ore Squidshark Egg Titanium Gold Trivalve Egg Uraninite Crystal Young Cotton Anemone

Deep Purple Vents

This continuation of the Purple Vents biome descents into caverns located deeper yet still possesses much of the same characteristics that make the shallower variant distinguishable: the eponymous hydrothermal vents that spout extremely hot purple matter. There is little in the way of plant life, though, the Deep Purple Vents biome is one that has the rare and valuable Gel Sack.

Deep Purple Vents Points Of Interest

  • Fossil Excavator

Deep Purple Vents Databank PDA Entries

Deep Purple Vents Plants

  • Gel Sack Ragged Pitcher Plant Spiral Plant

Deep Purple Vents Creatures

  • Feather Fish Feather Fish (Red)

Deep Purple Vents Fragments

  • Seatruck Docking Module Fragments

Deep Purple Vents Resources

  • Crystalline Sulfur Ion Cube Lithium Salt Deposit Spiral Plant Clipping Uraninite Crystal

Deep Twisty Bridges

As one heads down deeper in the Twisty Bridges biome, this is where they will end up. The Deep Twisty Bridges are quite similar to their predecessor biome, however, everything here is exposed to less light, which gives this location an eerie feel; especially when one sees Squisharks lurking about.

Due to the sheer walls of this biome, it is recommended not to bring a Prawn Suit here, as it would be very difficult for the undersea vehicle to get out. It is worth noting that Gel Sacks can also be found in the Deep Twisty Bridges biome.

Deep Twisty Bridges Points Of Interest

  • Obelisk

Deep Twisty Bridges Databank PDA Entries

  • Seatruck Log #1 Seatruck Log #2

Deep Twisty Bridges Plants

  • Blue Barnacles Broken Mandrake Gel Sack Oxygen Plant

Deep Twisty Bridges Creatures

  • Blue Spikey Trap Spinefish Squidshark Triops

Deep Twisty Bridges Fragments

  • Seatruck Fabricator Module Fragments Seatruck Storage Module Fragments

Deep Twisty Bridges Resources

  • Diamond Gold Ion Cube Lead Lithium Magnetite Titanium

Twisty Bridges Caves

Subtle in difference from the Twisty Bridges biome that this Underwater Cave can be found in, it is not to be confused with the Deep Twisty Bridges biome as it has notably different resources. The way to tell this biome apart from others of similar name and description is that the Twisty Bridges Caves are enclosed by stalactite-covered ceilings. There isn’t much here, but it’s still worth taking a peek if stumbled across.

Twisty Bridges Caves Points Of Interest

Twisty Bridges Caves Databank PDA Entries

Twisty Bridges Caves Plants

  • Blue Barnacles Oxygen Plant

Twisty Bridges Caves Creatures

  • Arctic Ray Brute Shark

Twisty Bridges Caves Fragments

Twisty Bridges Caves Resources

  • Argentite Outcrop Brute Shark Egg Calaverite Outcrop Copper Ore Crashfish Egg Crystalline Sulfur Gold Silver Ore Titanium

Fabricator Caverns

In contrast to most biomes found in the game, the Fabricator Caverns are loaded with vibrant red crystals. This biome can only be accessed by traversing through the Crystal Caves biome, as one might be able to glean from the similarly shaped crystal formations. Also like the Crystal Caves, there are Shadow Leviathan prowling here, so be on one’s guard while exploring this location.

Fabricator Caverns Points Of Interest

  • Fabricator Base

Fabricator Caverns Databank PDA Entries

Fabricator Caverns Plants

  • Eclipse Plant Ribbon Plant

Fabricator Caverns Creatures

  • Bladderfish Feather Fish (Red) Rockgrub Shadow Leviathan Spinefish Triops

Fabricator Caverns Fragments

Fabricator Caverns Resources

  • Argentite Outcrop Calaverite Outcrop Copper Ore Gold Kyanite Large Quartz Deposit Large Titanium Deposit Limestone Outcrop Nickel Ore Quartz Ribbon Plant Silver Ore Titanium

Glacial Connection

Located under a glacier in the West Arctic biome, the Glacial Connection is an Underwater Cave in the form of a tunnel leading to the Glacial Basin biome. Being trapped under the ice can be a terrifying concept, therefore many players feel more comfortable traversing this tunnel in a vehicle while looking for resources, despite the fact that the narrow path makes it tough, albeit possible, for watercraft like Seatrucks to pass through.

Glacial Connection Points Of Interest

Glacial Connection Databank PDA Entries

Glacial Connection Plants

  • Creepvine Hardy Cave Bush Radiant Sieve Coral Ribbon Plant Violet Beau

Glacial Connection Creatures

  • Arctic Peeper Bladderfish Eye Jelly

Glacial Connection Fragments

Glacial Connection Resources

  • Copper Ore Creepvine Sample Galena Outcrop Ion Cube Eye Jelly Egg Lead Limestone Outcrop Magnetite Ribbon Plant Silver Ore Titanium

Koppa Mining Site

Beneath Delta Island, there is this formerly Alterra Corporation-owned mining site designed to harvest large quantities of resources from the planet. When one makes their way here, they will likely find tons of Prawn Suits left behind after Alterra abandoned this location and all the goods here, which means it perfectly fine for the player to loot the Koppa Mining Site to their heart’s content!

Koppa Mining Site Points Of Interest

  • Alien Statue Lava Geysers

Koppa Mining Site Databank PDA Entries

  • Aurora Wreckage Located, Survivors Confirmed Mining Site Delivery Was Unexplained Ion Signature Linked to the Aurora’s Disappearance?

Koppa Mining Site Plants

  • Oxygen Plant

Koppa Mining Site Creatures

  • Feather Fish (Red) Rockgrub Rock Puncher Triops

Koppa Mining Site Fragments

  • Habitat Builder Fragment Laser Cutter Fragment Light Stick Fragment Prawn Suit Drill Arm Fragment Prawn Suit Fragment Thermal Plant Fragment

Koppa Mining Site Resources

  • Argentite Outcrop Copper Ore Diamond Gold Large Copper Ore Deposit Large Diamond Deposit Large Gold Deposit Large Ruby Deposit Large Silver Deposit Large Titanium Deposit Rock Puncher Egg Ruby Silver Ore Titanium

Lilypads Crevice

Like the Deep Lilypads Cave, the Lilypads Crevice biome can be found beneath the Lilypads Island biome. This network of nooks is within the seafloor and if one wants to find it, they’ll have to keep their eyes peeled for the subtle crack-like entrances.

There is a great variety of vegetation to be found in the Lilypads Crevice biome, including Gel Sacks, so be sure to explore this deep green den if one is looking for rare resources.

Lilypads Crevice Points Of Interest

  • Marine Life Analyzer

Lilypads Crevice Databank PDA Entries

Lilypads Crevice Plants

  • Antennae Plant Blooming Raindrops Gel Sack Green Ternion Hivemind Lilypad Oxygen Plant Paddle Fern Purple Cattail Radiant Sieve Coral

Lilypads Crevice Creatures

  • Brown Spikey Trap Lily Paddler Sea Monkey Spinner Fish

Lilypads Crevice Fragments

  • Prawn Suit Grappling Arm Prawn Suit Thermal Reactor Seatruck Afterburner Upgrade Seatruck Horsepower Upgrade Ultra-High Capacity Tank

Lilypads Crevice Resources

  • Calaverite Outcrop Copper Ore Gold Large Silver Deposit Lily Paddler Egg Limestone Outcrop Nickel Ore Ruby Titanium

Thermal Spires Caves

Dark and obscured by hydrothermal vents spewing dank clouds, the Thermal Spires Caves are very hot and easy to get lost in, so be sure to bring a Flashlight. This biome can be entered from the Thermal Spires biome located higher up, near Delta Island. There isn’t too much to be looted from this locale, however, this area can be used as an alternate route to the Koppa Mining Site.

Thermal Spires Caves Points Of Interest

  • Mineral Distillery

Thermal Spires Caves Databank PDA Entries

Thermal Spires Caves Plants

Thermal Spires Caves Creatures

Thermal Spires Caves Fragments

Thermal Spires Caves Resources

  • Argentite Outcrop Cryptosuchus Egg Diamond Galena Outcrop Gold Lead Limestone Outcrop Silver Ore Titanium

NEXT: Subnautica: Below Zero - Everything You Need To Know About The Ice Worm Leviathan