Pier

From Nookipedia, the Animal Crossing wiki

The dock is the access point to the Island in Animal Crossing and Animal Crossing: New Leaf. It is also the location that the player can find Kapp'n.

In Animal Crossing

File:Kapp'nBoat.png
Kapp'n in his boat in Animal Crossing

In Animal Crossing, the dock is located at the south of the town, on the ocean. The dock will be empty and useless, until the player connects a Game Boy Advance to the GameCube via a Nintendo GameCube Game Boy Advance Cable. Once done, Kapp'n will appear at the dock on a small rowboat, and will offer the player a free boat ride to the island.

In Animal Crossing: New Leaf

File:Kapp'n and Motorboat.png
The dock from which Kapp'n will take the player to the island from in New Leaf

After meeting certain conditions, the player can access the Island by meeting Kapp'n at the town's dock, similar to Animal Crossing. Unlike the previous game, however, Kapp'n can now carry up to four players to the island at once, and also charges 1000 bells for the service. Also, a basket will be there to transport your things to and from the Island (e.g fish).