The Ocean is a large, deep body of water that always spawns at both ends of a world.
Oceans are biomes that spawn only at either end of a world. Typically, the background will change to sandy islands sparsely overgrown with palm trees and appear to be partially submerged. Oceans always reach the end of the map, however they usually will not extend past it.
When you reach the ocean proper, the ground will usually change to sand, however unlike deserts, there will not necessarily be cacti. The sand will rapidly drop off into water, and any submerged sand blocks may have coral growing on them.
Mobs exclusive to the ocean include:
Through experimentation, it has been determined that it is possible to create a fully functional artificial ocean. For an area to be considered an ocean, it must meet the following requirements:
- Have a floor of sand at least one block thick.
- At least one block of water.
- Must be at least 1/3 of the way from spawn.
- Coral that grows on the ocean floor is key to traversing this biome with minimal effort, as it can be used to make Gills Potions.
- Creating an air tunnel along the floor of the ocean is an easy way to make your way across, but it is very tedious work. Further exploration and experimentation has shown that should you make a hellevator in this air tunnel and dig a hole through your tunnel, the ocean will pour through. When the first bit of water hits the underworld, the water evaporates (as of 1.0.5). When this happens, all water that is falling and would eventually fall to The underworld instantly disappears, leaving only what ocean water would remain (water that didn't have an open path to fall through). This proves that the ocean is not infinite and can be removed from your world if you wish to do so.
- Drained oceans are treated as deserts, including spawning all of the appropriate monsters. In Hard Mode, they can even become Corrupted or Hallowed. Normal oceans can also be Corrupted or Hallowed.
- Corrupted or Hallowed oceans will not spawn Sharks.
- This biome can spawn Water Chests, with their own particular set of loot possible.
- A good weapon and a Breathing Reed or Flipper make exploring the Ocean much easier.
- It is possible for no Water Chests to spawn on the ocean floor.
- On rare occasions, the map stops but allows you to go on, thus being able to travel to the underworld without digging.
- Occasionally, the water on the very edge of the map may become "stuck", and will only be viewable with third party tools.
- When walking down to the bottom of the ocean occasionally you will take suffocation damage when using Hermes Boots, even with a full Breath Meter.
- Sometimes, although very rare, the water will not spawn. Instead, a very large and open cave is in its place. This appears to only happen on iOS versions of the game. It will act as a normal cave, spawning the appropriate monsters.
- On very rare occasions an underground structure will spawn in the ocean.
- Occasionally, one of the islands in the background will have a half-buried moai on it, a reference to Easter Island.