Island hopping is the theme of this watery World, and it will test your jumping ability. Don't go through the area too fast, or you may run into an enemy ambush.
The jumping fish known as the Honhen are only a threat if you run into their sides. If they hit you from directly underneath, they will defeat themselves.
Drop down the first pipe that you encounter to discover the coin room shown to the right. A total of 78 coins can be had here. On top of that, there are two power-ups hidden in the room. Break blocks and use a Superball to get all of the coins.
Score coins twice. Before entering the coin room, collect coins from the Multi-Coin Block. Enter the pipe and collect all of the coins. Then exit and get the coins outside again.
Drop down the pipe to enter the coin room shown to the right. There are 20 coins in this room, but the question is how do you reach them. Reveal the hidden block on the right side of the room to create a platform to jump up and escape.
There's a 1-Up Heart just before the end of the level. To collect it, you must be big. Break the first block on the bottom, then hit the block above it. As the Heart falls, jump to the platform where the coins are to collect it.
Meet the Mekabons — robots that lose their heads when Mario is around! This world isn't too difficult, although there are a couple of jumps you need to make while being harassed by enemies.
You'll be greeted by a Mekabon. The Mekabon's head serves as its weapon. It will regularly launch it in search of Mario. Your best bet is to quickly stomp the robot before it attacks.
The first pipe leads to another coin room, shown right, which holds 78 coins. In addition to the ones you can see, there are a few more coins tucked away inside one of the blocks. Pop them out before you leave.
A secret pathway awaits you at the end of this section. But only small Mario can access it.
To reach the lower passage of this section, you must use an invisible floor that sits just above the water. You must be small to fit into the passage. Although you'll be giving up the chance to collect an Invincibility Star, you'll collect more coins. Don't miss the power-up just before the pathway ends.
The last pipe leads to the coin room, shown to the right. It has another 20 coins, and you'll need to find the hidden block which can get you up to the top, this time closer to the left side of the room. One of the blocks below the exit pipe actually contains a few more coins for you to discover.
It's difficult to reach the upper exit of this world. You'll have to quickly hop up the small dropping lifts to make it.
In this underwater area, you'll have to man the Marine Pop and blast your way through the defenders. The automatic scroll won't cause trouble unless you fail to blast blocks.
The large octopuses are called Gunions. After you shoot a Gunion, it will explode into deadly fragments, so be ready to dodge. You can also just go around the passive octopi.
Create gaps in the block walls large enough for the Marine Pop to fit through. Hidden in some of the blocks are power-ups that can make the Marine Pop increase in size.
