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"The depths of the underground desert are rumbling..."

The Sunken Sea is an aquatic biome added by the Calamity Mod which spawns upon world creation. It is located directly underneath the Underground Desert. Comprising it is a series of caves almost entirely filled with water, illuminated by glowing blue Prism Shards.

It is filled with numerous sea creatures, most of which are peaceful until provoked, including the Giant Clam mini boss. The biome becomes more populated once Hardmode begins, and several existing enemies receive new abilities and item drops.

It is composed primarily of Navystone and Eutrophic Sand, as well as Prism Shards scattered throughout. Giant floating Geodes are located throughout the biome, which are composed of a Navystone shell and Prism Shards attached to Sea Prisms inside. There will always be a Geode at the center of the entire biome, which is also the largest Geode. A large variety of different corals and other ambient objects also generate in this biome. The Table Corals can be stood on, the Fan Corals produce light, and the Brain Corals can produce bubbles that the player can touch to gain the Gills buff, with small ones granting it for half a second, and larger ones granting it for 1.5 seconds. Nothing in the Sunken Sea can be broken until the Desert Scourge has been defeated.


Sunken Sea
CharactersUnique DropsMusic
Eutrophic RayEutrophic Ray
Ghost BellGhost Bell
Sea FloatySea Floaty

If Desert Scourge has been defeated:

Giant ClamGiant Clam(Miniboss)

In Hardmode:

Blinded AnglerBlinded Angler
Sea SerpentSea Serpent


Baby Ghost BellBaby Ghost Bell
Sea MinnowSea Minnow

From Eutrophic Rays after defeating Desert Scourge:

Eutrophic ShankEutrophic Shank

From Ghost Bells after defeating Desert Scourge:

Voltaic JellyVoltaic Jelly

From Prism-Backs after defeating Desert Scourge
and Blinded Angler:

Prism ShardPrism Shard

From Blinded Anglers:

Eutrophic ScimitarEutrophic Scimitar

From Sea Serpents:


From Baby Ghost Bells caught with a Bug Net:

Rusted Jingle BellRusted Jingle Bell

From Giant Clams after defeating Desert Scourge:

Giant PearlGiant Pearl
Amidias' PendantAmidias' Pendant

From Giant Clams in Hardmode:

Clam CrusherClam Crusher
Clamor RifleClamor Rifle
Shellfish StaffShellfish Staff

From Clams and Giant Clams in Hardmode:

Mollusk HuskMollusk Husk

From terrain:

Eutrophic SandEutrophic Sand
Sea PrismSea Prism
Prism ShardPrism Shard

From Fishing:

Coralskin FoolfishCoralskin Foolfish
Greenwave LoachGreenwave Loach
Prismatic GuppyPrismatic Guppy
Rusted Jingle BellRusted Jingle Bell
Sparkling EmpressSparkling Empress
Sunken CrateSunken Crate
Sunken SailfishSunken Sailfish

From Fishing during Hardmode:

Scarred AngelfishScarred Angelfish
Serpent's BiteSerpent's Bite
Music Box (Sunken Sea)Music Box (Sunken Sea)


  • Player-created Sunken Sea biomes are possible by placing more than 150 Eutrophic Sand, Navystone, and/or Sea Prisms in an area.
  • The player is also considered to be within the Sunken Sea when standing in front of natural Eutrophic Sand Walls or Navystone Walls.
  • It is possible to find Lime Kelp in the Sunken Sea.
  • Only Sunken Sea mobs can spawn while the player is considered to be in the biome, and only in areas that have water. If there is no water or the only areas that have water have player-placed walls, no mobs can spawn.


  • Equipping any accessory which allows for extended or infinite underwater breathing (such as the Ocean Crest or Diving Helmet/Gear) will make exploring this biome much easier.
  • The Sunken Sea is a good place to go to obtain Life Crystals early in a playthrough; there are no traps, none of the enemies are naturally hostile, and the area is intermittently lit up by Prism Shards to make finding them easier. While Navystone may not be minable until Desert Scourge is defeated, there are still many places where the Sunken Sea can naturally be entered, and there are usually Minecart Tracks that open paths to explore even more of the Sunken Sea.
    • Note that other aquatic enemies (such as Jellyfish and Piranhas) can spawn in the Sunken Sea before the player is considered to be in the biome, so exercise caution when entering.
  • As the biome contains essentially no hostile mob spawns and its blocks have no corrupt, crimson, hallow, or astral variants, it is one of the safest places the player can put their home base, provided they can drain the water. Remember that Eutrophic Sand Walls will continuously spawn water, so removing them is advised to avoid the player's base being flooded.
    • Creating an artificial Sunken Sea is an alternative strategy for making a home base, however the surrounding areas will still be vulnerable to spreading biomes.


  • The theme heard while in the Sunken Sea is sanctuary, which was composed by the artist DM DOKURO.
    • The song's motif is the same as that of the theme of the Sulphurous Sea.
    • If the Calamity Music add-on mod is disabled, the Jungle Temple's theme will play instead.
  • The Sunken Sea seems to be what remains of the ocean that Calamitas incinerated, according to the lore.
  • Many of the enemies or items having the word "Eutrophic" in their names suggests that the Sunken Sea has undergone some degree of eutrophication, which results in an oxygen-depleted environment.
  • Oxygen depleted environments can lead to lethargic sea life in the real world, which may explain why the majority of this biome's enemies are passive until provoked.
  • Brain Corals producing oxygen bubbles may be a reference to the game Subnautica.
  • During the generation of the Sunken Sea in world creation, the message reads "Making the world more wet." This phrase was originally used to tease the implementation of the biome in the mod's changelogs.


All of life was born from the seas. It was from them that sprung the vast multitude of creatures today, though their beginnings were rather humble. Slimes formed out of gelatinous organic matter, and tiny worms from the earth and muck. Fish soon followed, and many fled to the deep unexplored caverns in the lands. Many coasts of the world were riddled with extensive cave systems, going miles deep. These unending tunnels and air pockets gave rise to a marvelous ecosystem. The critters fed, lived, and died in these caverns of darkness lit only by phosphorus bacteria, and radiant crystals. As time passed, and they became more and more adapted to those sheltered caves, there was less and less reason for them to venture outside, and so, centuries passed with no effect on these living remnants of history. They lost their eyes, their complexion, and so, were shaped by their environment. After tectonic shifts in the planet's crust, these subterranean paradises of marine life were isolated deep underground, where the inhabitants would wait, forever blind in the sunken seas.