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
- None
Crystal Castle Databank PDA Entries
- None
Crystal Castle Plants
- Sulfur Plant
Crystal Castle Creatures
- Crashfish
- Triops
Crystal Castle Fragments
- None
Crystal Castle Resources
- Crashfish Egg
- Crystalline Sulfur
- Diamond
- Kyanite
Crystal Caves Fissure Points Of Interest
- None
Crystal Caves Fissure Databank PDA Entries
- None
Crystal Caves Fissure Plants
- Jade Membrane
- Polycage
Crystal Caves Fissure Creatures
- None
Crystal Caves Fissure Fragments
- None
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
- None
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
- None
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
- None
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
- None
Twisty Bridges Caves Databank PDA Entries
- None
Twisty Bridges Caves Plants
- Blue Barnacles
- Oxygen Plant
Twisty Bridges Caves Creatures
- Arctic Ray
- Brute Shark
Twisty Bridges Caves Fragments
- None
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
- None
Fabricator Caverns Plants
- Eclipse Plant
- Ribbon Plant
Fabricator Caverns Creatures
- Bladderfish
- Feather Fish (Red)
- Rockgrub
- Shadow Leviathan
- Spinefish
- Triops
Fabricator Caverns Fragments
- None
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
- None
Glacial Connection Databank PDA Entries
- None
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
- None
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
- None
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
- None
Thermal Spires Caves Plants
- Oxygen Plant
Thermal Spires Caves Creatures
- None
Thermal Spires Caves Fragments
- None
Thermal Spires Caves Resources
- Argentite Outcrop
- Cryptosuchus Egg
- Diamond
- Galena Outcrop
- Gold
- Lead
- Limestone Outcrop
- Silver Ore
- Titanium