Super Mario Bros. 3/World 3

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.

Part 1

 * First, pass the two Roto-Discs and the Dry Bones by jumping over them.
 * This place is a small maze. Most of the doors just take you to a moat filled with Cheep-Cheep. If you want to see the miniboss, run forward and take the sixth door. This leads to part 2.
 * Taking the fifth door also leads into the moat, but on a platform where you can grab a 1-up mushroom.
 * Go all the way to the back and enter the last door to get to a bonus area (see below).

Part 2

 * If you took any of the other doors, you'll fall into the moat. Take any of the pipes, they all lead back to the same pipe at the beginning. The blocks here contain raccoon leaves.
 * If you took door six, you'll land at the top left platform, at the bottom door. Jump up to the top door and enter it to get to part 3.

Part 3

 * Run forward to meet Boom-Boom. This time, he has a new trick up his sleeve: once you stomp him once, he starts getting airborne. You must then wait until he swoops down on you to stomp him. Of course, you could just as well enter as Fire Mario and feed him five fireballs to avoid this.

Bonus area

 * You'll see a bunch of coins, but the obvious way through the holes reveals hidden blocks which block you off. Jump from the door, though, to discover another hidden block which allows you to go up to the coins to collect them.

3-4

 * The first block you see contains a raccoon leaf.
 * At the big slope, you can slide down to kill the Goombas, but watch out because the slide leads right into a pool with a Cheep-Cheep inside.
 * From this pool, there might seem to be no way to go further, but jump along the right side to reveal hidden blocks which lead you out.
 * On the next slope, you might want to not slide but instead to stomp one of the Koopa Troopas and take its shell. Use it to take out the red Para-Goomba in the next area, which can be a pain.
 * Once you see a Piranha Plant overhead, jump at the block directly to its right for a Fire Flower. Jump at the right brick block for a P-Switch, which will make coins appear in this area.
 * Continue to see another new enemy: Lakitu. He drops spinies at you from above, run quick to avoid these. Right where you see him, jump at the second brick block from the left for a 1-up mushroom.
 * At the end, jump at the last block for another raccoon leaf. At the goal card, you can try waiting until Lakitu drops four spinies, then collecting the card for a free 1-up.

3-5

 * As Raccoon Mario, start flying from the pipe to land on a platform made of wooden blocks. Wag your tail against the brick block here for some coins, then resume flying to land on another such platform. Again get some coins from the brick block, then jump into the water and you will have skipped most of the level.
 * The Frog Suit is of great advantage here. There are Jelectros in this level which are stationary enemies that hurt, and if you don't have the Frog Suit they can be rather annoying.
 * Drop down to find a new enemy, a Big Bertha. This one will not try to eat you unlike its surface brethren, but instead release small children from its mouth. The first block above it contains a Fire Flower, which you can use to kill it.
 * If you have the Frog Suit, keep at the bottom. Swim into the second pipe at the ground to get to a bonus area (see below)
 * After the large pit there's another group of blocks, the middle one contains another Fire Flower. Just after the gray structures, you can find a hidden 1-up mushroom (which is difficult to collect without the Frog Suit).
 * At the part with the two pipes and the group of Jelectros, you may want to lure the blooper ahead a bit away, otherwise it may hurt you while you try to swim up.
 * The pipe at the end leads to the ending area. Jump on the wooden platform and from here, run to get the goal card.

Bonus area

 * Hold to the right to get to a giant ? block, jump at it to get three 1-up mushrooms! Afterwards, exit the area, you'll return at the part with the group of Jelectros.

3-6

 * This is another autoscrolling level. The first block contains a Fire Flower.
 * Watch out when you see the first lift. It can screw you over by launching you right down into the pit. Jump after it has spun to get across.
 * On the first wooden platform, stomp on the Koopa Troopa, take its shell and drop down the donut platform. At the bottom, kick the shell between the brick block and the donut platform to get some coins.
 * On the second wooden platform, grab the ice brock, drop down, and kick the ice block against the brick block to get a raccoon leaf.
 * The gaps after the Para-Troopa are quite large and require very precise jumping skills. They're easier if you're Raccoon Mario who can soar.
 * When you land in the area with three ice blocks, kick one against the brick block to the right to reveal a P-Switch. Step on it to transform the brick blocks into coins. Jump at the single "coin" above you for a 1-up mushroom.
 * In the ending area, you only need to look for the patrolling Para-Troopa. Afterwards, you can run and grab the goal card.

3-7

 * Right at your beginning position, bump from the side into the topmost wooden platform for a raccoon leaf.
 * You'll encounter a new enemy here, Spike. He throws spike balls at you, but you can defeat him like any other enemy.
 * You should stumble upon a group of brick blocks. Don't touch them, you'll return here later.
 * At the area with the single Koopa Troopa and three Spikes, bump into the bottom-left wooden block for a Fire Flower. Then, climb to the top and jump to the top-left brick block to reveal a vine. Climb the vine from the nearby green platform, and once up, follow the cloud platforms to the left. The brick block there contains a P-Switch, step on it then run to the left and drop down to return to the group of brick blocks, only that they're all coins now. One of them hides a 1-up mushroom.
 * After you have climbed the vine, instead of running left, jump onto the wooden block and jump to the right. You'll land on an isolated cloud platform, jump at the middle to uncover a pink note block leading to a Coin Heaven (see below).
 * Near the end, when climbing the blue structure, watch out for the green Para-Troopa coming your way.

Coin Heaven

 * This is an autoscroller. Walk to the end, collecting all the coins on the way, to get to a treasure chest. It contains a Jugem's Cloud, you'll then automatically exit the level.

Part 1

 * This is a level where the Frog Suit is very helpful. Enter the pipe in the water to proceed to part 2.

Part 2

 * Since the Roto-Disc spins clockwise, you might want to swim above, rather than below it.
 * Two Cheep-Cheep are guarding a block containing a Fire Flower here. Grab it if you want it, then continue.
 * The pipe at the end leads to part 3.

Part 3

 * Here, you'll encounter a new enemy: Stretches. These are essentially Boo Diddleys stuck to a white block. They can still do damage to you if you aren't careful.
 * Avoid the first group by swimming barely above the pit. For the second one, swim up to the ceiling. After that, you have to swim between the two last Stretches, which is very hard without the Frog Suit.
 * The pipe at the end leads to part 4.

Part 4

 * Run forward to meet Boom-Boom again. This time, there are two blocks in his room, which can either help or hinder you. Stomp on him three times or feed him five fireballs to defeat him.

3-8

 * This level has Boss Bass again to eat you. The blocks move farther than they did in 3-3, so watch out.
 * Jump on the first pillar, then wait until the blocks move down. When they move up again, go forward and kick the Koopa shell against the left block to reveal a vine. Climb it up to safety and jump on the note block to reveal a fire flower.
 * When the blocks move up again, continue to jump until you're on a platform with ice blocks. Kick them away, then jump at the brick block for some coins.
 * There's a single brick block with a 1-up mushroom. You need to be Raccoon Mario to get it.
 * Kick the next Koopa Troopa against the right brick block to reveal another vine where you can hide from Boss Bass. Two platforms further, there's yet another vine in a brick block.
 * Before the end, the path splits into two. The shorter and by far easier way is the top one, which leads straight to the pipe. The bottom one leads to several coins and a P-Switch which turns the brick blocks here into coins. You can then get a 1-up mushroom from the topmost "coin".
 * Collecting 44 coins in this level unlocks the White Mushroom House. This requires taking the bottom route to get the coins there and using the P-Switch.

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.