Ocean

The Ocean is a large Water body found on the surface of each map, at its far left and right edges, comprising the eastern 500ft (250 blocks) and the western 500ft of the map. It extends as deep as the Cavern Layer, with its maximum depth reached at the very edges of the map.



Oceans will commonly contain chests with loot pertaining to water. They also contain unique enemies, like Crabs and Sharks.

Strategies
Unique items attainable in the Ocean include the Shark Fin and Diving Helmet (dropped by Sharks), and Coral (grows on the Ocean floor). There are also chests, though they rarely contain items that aren't also available elsewhere.
 * If players without proper accessories try to swim to the side of the map, there is a serious risk of drowning. In addition to plenty of healing potions, it is advisable to bring items and potions that aid in breathing, such as the Breathing Reed and Gills Potion, a Magic Mirror for returning home quickly, and Flippers to aid swimming. The Grappling Hook or Ivy Whip may also be of some help in returning to the surface for breath.
 * Players may attempt to drain the ocean by tunneling down to the Underworld, where water evaporates. The Ocean is in fact drainable this way, and this method will allow the player to go back to the Ocean floor and easily pick up all the Coral without worry of suffocating. However, no Sharks will spawn once the Ocean is drained, and previously-spawned Sharks will have vanished. Therefore, draining will not allow a player to obtain Shark Fins and the Diving Helmet.
 * For looting Ocean chests, generate a small or medium-sized map. Then, using the Necro Armor, Hermes Boots, Anklet of the Wind and other speed boost items, run from one side of the map to the other. Since there is a good chance to have some Chests in the ocean, it is an easy way to get medium-tier items. The chests will usually contain items such as Breathing Reeds, Shurikens, Magic Mirrors, Dynamite and Coins. When doing this, a Magic Mirror is also helpful, so that you don't need to run all the way back.