After running through the Gold Ring, you will come across three floating barrels. Bounce on a Cheep Cheep to reach the Star Coin above.
After the Checkpoint Flag, you will see a pipe with a Piranha Plant popping out. Use the pipe to wall jump on the blocks and to get the second Star Coin.
Just after the second gold ring are barrels wedged between three pipes. Stand on the barrel to the right to cause it to sink and reveal the last Star Coin.
Right at the start, you will see a Star Coin inside a whirlpool. Wait for it to subside and claim your Star Coin.
After the Checkpoint Flag, there will be a yellow pipe stuck between two whirlpools. Carefully swim over the top of the pipe and enter it. The next room will be full of – with a Star Coin in the middle. Wait for the right opportunity and grab it.
On your way to the end, you will come across a section full of Snake Blocks. A Star Coin rests near the top of the section, and you will have to get it while avoiding Deep-Cheep.
Early in the level, hit the red switch just above the spider web to uncover the hidden platform below and use it to enter the yellow pipe. Inside, hit the red switch to create a platform that leads to the Star Coin. Wait until the Scuttle Bug lowers to hop on and grab the Star Coin.
After the Ckeckpoint Flag, enter the yellow pipe that can only be accessed by jumping from the spider web to the Scuttle Bug. Inside, hit the red switch and start jumping on the platforms. Hop over the Scuttle Bug, then turn back around and hop on it to get that extra boost needed to grab the Star Coin.
This is an easy one. On your way to the end, hop from one spider web to the other to collect the last Star Coin.
At the very beginning, go left instead of right and swim into the gap in the corner. Inside you will find the first Star Coin.
Just before the area with the giant spikes, there will be a Star Coin to your right. Avoid the Fishbones and you should be fine.
In the area with the Red Ring, enter the green pipe on the left. Inside, swim over and collect the last Star Coin.
Use the Wiggler as a boost to snag the first Star Coin at the beginning of the level.
At one point, you will come across three crates aligned together. Jump into the cave on the right and grab the Star Coin at the end. Be quick, as the poison water will rise and kill you if you are still inside.
Right after the second Star Coin, jump onto the two crates and use a wall jump to grab the last Star Coin. Again, watch out for the poison water.
After entering the first room, ride the platform moved by Peepas until the very end. Make sure you get the Boo to move away from the Star Coin, and grab it just as the platform is disappearing.
In the fourth room with all the doors, use the middle moving platform to reach the second Star Coin. Alternatively, you can use Raccoon Mario to fly to the Star Coin.
In the same room as the second Star Coin, use the moving platform on the right and go through the door that is furthest from the second Star Coin. Inside, ride the moving platform until it reaches the end, a make a jump for the last Star Coin.
On your way through the level, you will see a Star Coin trapped with a Blooper behind unbreakable blocks. Swim a little higher and let the giant rock crash into the blocks. With the blocks gone, go and claim your first Star Coin!
Just after the first Star Coin, you should find a yellow pipe that leads to the next Star Coin. The Star Coin is easy to get, but the line of Bloopers are the real threat. No worries, as you can avoid them all by staying close to the very bottom.
Same deal as the first Star Coin, wait for the giant boulder to come forward and crush the unbreakable blocks.
The first Star Coin will be seen on the left in open sight. Atop the tiny platform beneath the Star Coin is a hidden block. Hit and create a block that will allow you to grab the Star Coin.
After the first giant spike, the second Star Coin can be seen on a platform near the water. Wait for the two spikes to pass and grab the Star Coin.
Don’t enter the door to the boss. Stand against the right wall and hit the hidden block above. Use it to jump over the wall and into a room filled with coins and the final Star Coin.
After passing by all the Cheep-Cheeps, stay near the top and you should see the Star Coin.
As soon as you leave the red pipe, enter the gab beneath the ring of Cheep-Cheeps. Hit the switch to stop the water current and grab the second Star Coin at the end.
Continue making it to the end and you should see the last and final Star Coin as you are making your way through the sea of Urchins.
You must enter the red pipe and not the yellow pipe at the beginning of the level. This goes for all three Star Coins.
As you are hopping as Mini Mario, jump on Paratroopa to boost your way to the first Star Coin.
There will be a small pipe at the top of the screen about halfway through the level. Enter it and use the Bullet Bills to continuously jump as they move to the right. The Star Coin will be near the end.
Near the end, run and jump onto the set of bricks and wall jump to the third Star Coin. You will need to be quick, as the screen can crush you.