Hit the ? Switch at the bottom of the long drop at Point 1 to fill the level with water. Swim up to the surface of the water before it drains and you drop back down.
Wall-Jump up the gap at Point 4 to find a secret area with several coins and a power-up.
On the other side of the pipe is the next Star Coin, but you’ll need to get to it by a different route.
Hit the ? Switch at Point 6 to fill the room with water. Swim down and around as you grab the coins. Follow the coins up the gap to the level’s exit.
