The level takes place underwater and the player must avoid the Urchins found in this level. There are also some rapids that can pull the player to a bottomless pit.
- Star Coin 1: Before entering the first pipe, pass the pipe to reveal a hidden area. Wall jump and then run left to the first Star Coin.
- Star Coin 2: Go under the eighth Mega Urchin while following the current to the Star Coin. Swim up afterwards to avoid death while also avoiding the Mega Urchin.
- Star Coin 3: In Fire form (unless you're Nabbit), go to the trail of Urchins right after the eighth Mega Urchin and shoot fireballs at the Urchins to get the Star Coin.
Hidden Luigi image
Near the P Switch after the third Star Coin shows a pretty big picture of standard Luigi from Super Mario Bros. jumping.