World 3 is an beach-like level taking place in a tropical ocean. The levels all take place a large island filled with beaches and palm trees. World 3 is the first world to have a ghost house, and the boss of this world is Cheepskipper. The world has a total of 9 levels, with 3 being optional.
World 3-1: This level mostly takes place underwater. In the beginning, a pipe takes the player from an outside group of small islands into an underwater ocean. Many Cheep-Chomps lurk in the water, and will gulp down Mario if encountered. The first two star coins can be achieved by entering empty pipes lodged between bubble spewing pipes, and both are located after the checkpoint. The last star coin can be accessed with a P-switch. This level features fishes of all types, including Cheep-Cheeps and Cheep Chomps.
World 3-A: This level is an optional one, and can be accessed by paying 5 Star Coins. It is located near World 3-1 on the map, on the same beach. This level takes place right above the water, where many Skeeters swim about the surface of the water. The Skeeters drop bombs into the water, and they have to be used at one point in the level to destroy the blocks surrounding the first Star Coin. There is also a bonus area containing another Star Coin, too.