World 3 is called Ocean Side. The levels you find here are primarily water themed, which makes the Frog Suit ideal for many (but not all) of the levels. This world is much longer than the previous ones were, with nine levels and two fortresses.
The map contains multiple pipes. They have been colored here, pipes with the same color connect together. Another feature of this map is the bridges - they go up and down when you beat a level, and you can only cross them when they're down.
There are two Hammer Bros. here. Note that if the Hammer Bro is standing on the water on the world map, there will be a bit of water in the fight, which is a problem if you're small Mario. One awards a starman, the other awards a Hammer. Using the hammer on the rock next to 3-5 allows access to the canoe. You can use the canoe to sail to two remote islands, they consist of some mushroom houses and spade panels.
The mushroom house at the top left has only a Frog Suit. The other ones still have the traditional three-way choice, but, except for the one on the top-right island, have foregone the Super Mushroom in favor of the Frog Suit.
3-1
- If you got the Frog Suit from the secret mushroom house in World 2, this is the ideal level to use it in. If you didn't, drop down at the very beginning to find a block with a Fire Flower.
- Many of the pipes here have water currents which push you away from the pipe (these are marked on the map). Unless you have the Frog Suit, you cannot swim against the current.
- The first enemy you'll encounter here is a Blooper. It just swims around in an attempt to hit you. Unless you are Fire Mario, you cannot hurt it, so just avoid it.
- If you're not Frog Mario, at the part where the path goes down, swim to the surface and jump out of the water. Run over the wooden structure to get to a small hole where you can find another Fire Flower.
- If you chose to go down, you'll soon encounter a Lava Lotus. These spit out small fireballs that move slowly and hurt you. Quickly swim past to avoid them. Above the second Lava Lotus, the left block contains a Fire Flower.
- After the gray structure, drop down to come into an area full of note blocks that push you around. At the end, you'll find a brick block with a 1-up mushroom inside. It will soon fall into the pit below though if you don't collect it fast enough.
- The pipe at the top right takes you to the ending area which is empty apart from the goal card.
3-2
- In this level you'll encounter donut blocks. These blocks fall down if you stand too long on them, so watch your step.
- The first block contains a Fire Flower.
- Jump onto the wooden platform, and as soon as you see the wooden blocks, bump into them from the side to reveal a starman, which helps a lot against the Cheep-Cheep jumping out of the water.
- The blocks on the way contain continuous starmen. "Continuous" means that they'll only be starmen if you're still invincible by the time you bump into the block (otherwise, it will be just a single coin).
- When you see brick blocks over your head, jump to the third one from the left to reveal a P-Switch. This turns the coins below into brick blocks, get to them then jump to the left of the coin overhead to reveal a hidden 1-up mushroom. You can then jump to the pipe when the Piranha Plant is inside.
- Behind the pipe there's a block with a Fire Flower. You need to fall into the water to get it.
- The pipe takes you to the ending area. If you're Raccoon Mario, fly straight up to find a wooden platform moving around in circles. Stand on the left tip and jump when it's at the very left to reveal another 1-up mushroom.
3-3
- The terrain in this level moves up and down constantly. In the water, there's a Boss Bass, which will try to eat you if you're too close to the surface, which means instant death. While you can kill him, he will just regenerate, so it doesn't help a lot.
- Jump onto the first note block to make a Fire Flower fall down. To get it, stomp on the Koopa Troopa and kick its shell against the brick blocks to the left. You can then reveal a P-Switch which will allow you to get the Fire Flower.
- In this level, you'll see red lifts that spin around. Watch out to not fall into the water.
- The brick block in the air contains another Fire Flower. Beside it there are ice blocks, which you can kick around like Koopa shells. Use it on the brick block at the ground to reveal a P-Switch, jump on it to make the coins ahead form a bridge to the pipe.
- Way past the pipe, there's an isolated platform with a 1-up mushroom. You can either fly there as Raccoon Mario, or try to swim over there (extremely hard).
- The pipe leads to the ending area, which is empty apart from the goal card.
Fortress
This fortress has no enemies not in the previous fortresses. There is a row of 9 doors. Most of the doors will take you into a room with water at the bottom that can be exited by going to the left and entering the vertical pipe. The fifth will lead you to a 1-Up. The sixth will take you to Boom Boom's room. This Boom Boom will fly after the first stomp.
3-5
Use a Frog Suit in this level. A new kind of enemy, the Jelectro, is in this level. Only if you have a Frog Suit, you can enter a pipe with 3 1-Ups!
3-6
A side-scrolling level introducing Rotary Lifts. The first ? block contains a fire flower, which you probably shouldn't get if you're Raccoon Mario. Be very careful when getting to the pipe at the end leading to the Goal Panel.
3-7
This level introduces Spike. Break a brick with a Troopa shell and get a green vine. Going to the left will lead you to coins and a P-switch. Then, go back to the vine. Go right and if you land on a group of clouds, get a beige block and jump high above it to get to a coin heaven containing a Jugem Cloud.
Fortress
This fortress is just about all water except Boom Boom's room. Start it by entering the pipe. This room has Cheep-Cheeps and Rotodiscs. After the pipe at the end of this room, the next one has Stretches, a Boo Diddly inside a bar. Boom Boom has new blocks in his room to make it harder.
3-8
This level has Boss Bass once again. There are several Vines you can use to avoid getting eaten. You can get a visit to the White Mushroom House if you get 44 coins.
3-9
Bob-Ombs are in this level. There are two ways to get to the water part; either enter the pipe in the middle with Raccoon Mario or enter the pipe at the end covered by ice blocks. After going down either of these, enter the water of this level and go all the way to the left. Enter a pipe and get a Frog Suit! After exiting the room, go right and follow until the final pipe. Enter it and you've reached the Goal Panel.
(Variant: In Super Mario All-Stars, the ice block locations were changed slightly to prevent a glitch in which Mario can go down the side of the pipe.)
Canoe Ride
If you have a hammer, you can break a rock and get a canoe ride to 2 Toad's Houses and 2 Spade Panels. However, there is also the option of saving the hammer for World 4. There is also another toad house if you continue right.
Airship
The king has been transformed into a Spike. This airship has the same enemies as the first 2, plus Rocket Engines, which blow from cannons that look just like Bullet Bill cannons. Wendy O. Koopa throws rings, and she must be stomped on 3 times just like the first two Koopas. After stomping on her, you can get her wand and get a message from Princess Toadstool and a music box.