Goomba Towers are found throughout this area. Don’t be blindsided by them while rushing through.
Stamp
Grab a Mega Mushroom, and stomp your way forward until you reach a floor made from Rock Blocks, with eight more Rock Blocks floating above them. Destroy those floating blocks to find the Stamp.
Green Star #1
This wall of Blurkers can be dispelled simply by blowing into the GamePad microphone, or by attacking it with ranged Power-Ups. You can then wall jump inside the alcove to reach the Green Star.
Mind the Bloopers and the water vents here. The water vents are particularly dangerous, as they can occasionally push you into enemies and Spike Blocks alike.
When you reach a set of Rock Blocks on the sea floor, swim upward to find a hidden ledge area. Retrieve a Mega Mushroom from the ? Block there.
Green Star #2
With the Mega Mushroom, rush forward until you reach a set of Mushroom Trampolines. Ground pound on those Mushroom Trampolines to launch yourself up through two layers made from Rock Blocks. The second star is beyond the second wall. This can be done only if you’re empowered by the Mega Mushroom!
Near the second Green Star is a pipe leading to the end of the level. However, if you swim up toward the rays of light coming from the roof overhead, you can find another pipee leading to a bonus area.
Green Star #3
The bonus area fills with tall rows of Blue Coins once you hit the P Switch. Grab a Mega Mushroom from the nearby ? Block to make sure that you can reach all of the Blue Coins in time to earn the final Green Star. There are three waves of Blue Coins, and you can’t hope to collect all of the Blue Coins without the power of the Mega Mushroom.