World 4-1 (New Super Mario Bros. Wii)
From the Super Mario Wiki
This level has two choices right from the start-platforms or water. The player can clear the level by jumping on platforms or only being in the water. This level has Urchins, Big Urchins, Cheep Cheeps, Spiny Cheep Cheeps, and other enemies like those.
A Penguin Suit is required for all three Star Coins.