Underwater Islands
Unique biome featuring floating rock formations suspended by gas deposits. Rich in rare resources and tech fragments.
Quick Facts
Overview
The Underwater Islands are one of the most surreal biomes in Subnautica 2. Massive rock formations hover suspended in the water column at 100 to 250m depth, held aloft by pockets of gas trapped beneath them. The result is a dreamlike landscape of floating terrain — islands of stone and soil drifting in the open water, their undersides trailing gas bubbles that rise toward the surface. Between the floating formations, the open water is dim and quiet, creating a disorienting environment where up and down can feel interchangeable.
The floating islands are not just visually remarkable — they are rich in rare resources. Lead, Lithium, and Magnetite deposits are embedded in the floating rock, providing materials essential for advanced vehicle upgrades, reactor components, and specialized equipment. Fragment caches hidden among the formations contain scannable blueprints for technology that is difficult to find elsewhere. This combination of rare resources and unique fragments makes the Underwater Islands a high-value target for mid-to-late game exploration.
The biome is moderately dangerous. Bonesharks patrol the open water between formations, Stalkers nest on the larger islands, and Jellyrays drift through the gas-rich currents. The floating formations themselves can shift and occasionally dislodge rocks that fall into the water below, creating a physical hazard. The depth requires a vehicle or significantly upgraded oxygen capacity, and the disorienting three-dimensional terrain makes navigation challenging. Bring a Seamoth for depth and mobility, and be prepared to think in all directions.
Resources
The Underwater Islands are rich in rare resources not commonly found in shallower biomes. Lead, Lithium, and Magnetite are embedded in the floating rock formations, and fragment caches hidden among the islands provide valuable scannable blueprints.
Lead
Embedded in the floating rock formations. Used for reactor components and radiation shielding.
Lithium
From deposits in the floating islands. Essential for vehicle upgrades and reinforced plating.
Magnetite
Rare mineral found in the floating rock. Used for specialized equipment and advanced modules.
Creatures
The Underwater Islands support a mix of predators and ambient fauna. Bonesharks patrol the open water between formations, Stalkers nest on the larger floating islands, and Jellyrays drift harmlessly through the gas-rich currents. The three-dimensional terrain creates unique encounter patterns.
Boneshark
Aggressive predator patrolling the open water between floating formations. Attacks on sight.
Stalker
Territorial predator nesting on the larger floating islands. Drops Stalker Teeth when fed metal.
Jellyray
Harmless bioluminescent ray drifting through the gas-rich currents between formations.
Exploration Tips
Watch Your Depth
The Underwater Islands span 100 to 250m, and the floating formations create multiple depth layers. Track your depth carefully, as moving between formations can change your depth faster than expected. A Seamoth with a depth module is recommended for safe exploration.
Collect Fragments from Caches
Fragment caches are hidden among the floating islands and contain rare scannable blueprints. Prioritise finding and scanning these caches — they often unlock technology that is difficult to obtain elsewhere. Bring a Scanner on every dive.
Beware Falling Rocks
The floating formations are held aloft by gas pockets that can shift or rupture. When this happens, rocks and debris fall into the water below. Never hover directly beneath a large formation for long, and watch for trickles of gas bubbles that indicate instability.
Navigate in Three Dimensions
The floating terrain creates a disorienting three-dimensional landscape where traditional seafloor navigation does not apply. Use beacons to mark fragment caches and exit points. Maintain a mental map of which formations are above and below you to avoid getting lost.
Map Locations
The Underwater Islands float at 100–250m depth, typically found near the transition between mid-depth and deeper biomes. Use the interactive map to locate floating formations, mark fragment caches, and plan safe navigation routes through the three-dimensional terrain.
View on Interactive Map →Related Biomes
Mushroom Forest
150–300m — the peaceful Lithium-rich biome that often neighbours the Underwater Islands.
Twilight Zone
200–400m — the dim transition zone that overlaps with the deeper reaches of the floating formations.
Grand Reef
200–500m — the deep-water biome that the Underwater Islands can transition into at their deepest edges.
Related Guides
Resource Farming Routes
Optimized routes for gathering Lead, Lithium, and Magnetite from the floating formations.
Wreck & Databox Locations
Every fragment cache and databox site, including those hidden among the Underwater Islands.
Biome Progression Guide
Which biomes to explore and in what order. The Underwater Islands are a key mid-game target.
Frequently Asked Questions
What are the Underwater Islands?
The Underwater Islands are a unique biome featuring floating rock formations suspended by gas deposits trapped beneath them. The islands hover at 100 to 250m depth, creating a surreal landscape of floating terrain. Between the formations, the open water is dim and quiet, making navigation disorienting. The floating islands are rich in rare resources and tech fragments that are difficult to find elsewhere.
What resources are in the Underwater Islands?
The Underwater Islands are rich in Lead, Lithium, and Magnetite. These rare resources are embedded in the floating rock formations and are essential for advanced vehicle upgrades, reactor components, radiation shielding, and specialized equipment. Fragment caches hidden among the floating islands also provide valuable scannable blueprints for technology that is difficult to obtain in other biomes.
Are the Underwater Islands dangerous?
Moderately dangerous. The biome is home to Bonesharks that patrol the open water between formations, Stalkers that nest on the larger floating islands, and Jellyrays that drift harmlessly through the gas-rich currents. The floating rock formations can also shift and dislodge debris that falls into the water below, creating a physical hazard. The depth range of 100 to 250m requires a vehicle or upgraded oxygen capacity for safe exploration.
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