From Nookipedia, the Animal Crossing wiki
The Ocean is the most southerly point of the Animal Crossing series town. Despite being a sea, the Animal Crossing game's ocean has no tides, allowing the size of the beach to remain constant. The beach itself runs the length of the sea, with occasional breaks where outcrops lie, and where the river meets the sea. These outcrops, also known as capes, have small cliffs that separate them from the sea.
In Animal Crossing, the waves carry the lure on the fishing line towards the beach, while in Wild World and City Folk they carry it out to sea. If a house is located within close proximity to the ocean, then waves can be heard crashing against the shoreline from inside.
Where the ocean meets the land, a beach is located. Characters that walk on the beach will leave footprints that will disappear after a short time. Shells will wash up on the beach daily and occasionally (Wild World only) a note-in-a-bottle will wash up. In Wild World and City Folk only, coconuts will also wash up on shore and can be used by the player to grow palm trees, which produce two coconuts every three days. However, in order to grow into a palm tree, the coconut has to buried near the beach. Besides serving as a source for coconuts, palm trees also serve as a home to many rare bugs, such as the Elephant Beetle and the Goliath Beetle.
In Animal Crossing: New Leaf, in addition to being located along the southern side of the village, the beach is also located on either the eastern or western sides of the village as well. There may be a small portion of a beach that cannot be accessed normally without a wet suit, which allows players to swim and dive in the ocean. The wet suit also allows them to jump from cliffs and into the ocean or the sand.
A small number of special visitors can be found within close proximity to the beach and the ocean. On weekdays in Animal Crossing: Wild World, Pascal the sea otter can be found standing on one of the two capes by the ocean from 6 AM to 12 AM, where the player can listen to his diffuse and sometimes random thoughts. After the listening to Pascal, the sea otter will give the player a random ship-themed furniture before performing a perfect dive into the sea. In Animal Crossing and Animal Crossing: New Leaf, Gulliver the gull will wash up onto the shore infrequently. In Animal Crossing: City Folk, if Gulliver's U.F.O. is shot down, it will appear crashed on the beach the next day.