This is the third world of New Super Mario Bros. ULTIMATE. It is beach themed, with a little bit of mountain mixed in the middle. Wendy Koopa rules this land.
Seaside Resort 1
This level takes place by the shore. Mario begins by a small pond with some crabs and Cheep-Cheeps swimming around. Mario must pass them and travel the rest of the level, which is similar. The ending has a seashell that Mario can throw. It sends out a call and all the enemies in the level die. Mario must next cross a path of red and blue mushrooms that lead to the flagpole. The goal fortress is a sand castle in this level only.
- Star Coin 1: Mario must kill the crab in the second pond and head through a small gap in the bottom of the pool. This takes Mario to a secret underground room with a bunch of coins and the Star Coin. The pipe takes him to the checkpoint, skipping a quarter of the level.
- Star Coin 2: Slightly before the checkpoint, Mario can see the Star Coin on a deck high out of reach. When a Cheep-Cheep bounces out of the water, Mario must hop on it to reach the deck.
- Star Coin 3: Right before the flagpole, one of the blue mushrooms takes Mario to a coin heaven if Mario stands on it. The Star Coin is there.
Seaside Resort 2
This level is underwater. Mario begins by a pipe that takes him into the sea by some Cheep Cheeps. Mario must avoid them and some moving platforms. After there is the checkpoint. Bloopers are more common in this area. Mario must get past some pipes that form a maze, after which is the exit pipe. It takes him to an area in the middle of a lagoon with some mushroom platforms. This leads to the flagpole.
Seaside Resort 3
This level takes place on a cliff high above the seashore. Occasionally, a wave will come up. Mario should slide down the cliff and cross a tricky section with thin platforms and Piranha Plants. After this, Mario can get close to the shore where he finds some Cheep-Cheeps. Mario must cross until he gets to another section of the hill and the checkpoint. Mario must scale the mountain. At the top is a tsunami which will crush Mario if he doesn't avoid it with some platforms. He must avoid several more the same way. Right before the flag is a Banzai Bill Blaster.
- Star Coin 1: Right below the second platform in clear sight is the Star Coin on another platform. It is impossible to get if Mario doesn't hop onto a wave and swim to the Star Coin at the right moment.
- Star Coin 2: This coin can be very difficult to get without a Mini Mushroom. Instead of going up when the player gets to the mountain base, Mario must keep going forward and run past the spike balls and Piranha Plants. The Star Coin is there, next to a cannon pipe that will take him to the top of the mountain.
- Star Coin 3: This coin is impossible to get without a Mini Mushroom. When the player gets to the last tsunami, the player must quickly grab the coin under it and run back up with the Mini Mushroom.
Resort Secret 1
Mario must pay three Star Coins to unlock this level. It allows the player to skip the fortress when complete.
Seaside Resort 4
Seaside Resort 5
Resort Ghost House
The first Ghost House in the game is very challenging. It features the first appearance of the Boomerang Flower, which can be used to hit blue Boomerang Switches and kill Boos. Mario starts in the entrance to the house near some blocks and a blue Boomerang Switch in front of a huge gap near the door. Mario must hit a block to get a Boomerang Flower and then activate the switch, creating a bridge to the door.
- Left Door: This door takes Mario to a room with a narrow bridge and many coins. Mario must step on a P-Switch to make a path over the rickety bridge using the coins. There is a staircase and a door leading to the second floor.
- Middle Door: This door takes Mario to a room with a Big Boo. Mario can go right past it, but defeating it with a Boomerang Flower will unlock the secret exit.
- Right Door: The first Star Coin is in this room. The door leads to a network of staircases, a number of which are trick staircases and can send Mario to his doom. The stairs on the far right are the correct ones to take.
- Left Door: This door is only accessible by taking the middle door on the first floor. It leads to a room with many coins and three Big Boos. Mario must use a Boomerang Flower to hit a switch, killing the Boos. Mario can bypass the Boos and get a Star by going to the far left of the room and hitting an invisible block that has a Beanstalk, leading to a balcony and then the roof, where the flag is.
- Right Door: This door has the second Star Coin, located high on a ledge. Mario must avoid falling here, or he will fall back down to the first floor. Mario can either hit a P-Switch to cross a gap leading to the door or use a trampoline to get to a ledge with the Star Coin and a door leading to the roof, but this method can be very tricky.
- Middle Door: This door takes Mario to the most difficult section of the house, where he must battle a mini-boss, Bouldergeist. He is far easier to beat and can be defeated easily with a Boomerang Flower. If Mario doesn't have one, he can pick up the Bomb Boos like regular Bob-ombs and throw them back at Bouldergeist.
- This is where the flag is. Mario must get past the ghost garden and jump onto the flag.
Resort Secret 2
This level is unlocked by finding the secret exit in 3-Ghost House. Completing it will unlock the castle. It also has a secret exit, which will unlock the Green Switch Palace.
Green Switch Palace
This is a short level that takes place near a small house owned by Toad. He tells Mario that there is a surprise inside. Mario heads inside and hits the Green Switch, turning all dotted green blocks into Green Blocks. Completing this level takes Mario to World 3-7 that unlocks the cannon when complete.
Seaside Resort 6
Seaside Resort 7
This is only accessible by beating the Green Switch Palace. It is mountain themed, with high waterfalls in the middle. Mario starts near one and must become Mini Mario to traverse the water. After crossing the first area and touching the checkpoint, Mario will be forced to turn into Hammer Mario by using a Hammer Flower (found in a brick) and activate a switch after the checkpoint that will make a bridge to the next section. Mario must carefully time jumps off of Paratroopas to be able to get to the ending flag. Beating this level unlocks the second fortress and the cannon, which shoots to World 5.
Resort Tower 2
Seaside Resort 8
Seaside Resort 9
Resort Secret 3
Seaside Resort 10
This castle is owned by Wendy Koopa. Mario starts on a shore, where Mario heads into the castle courtyards. Mario can choose to go underwater with a green pipe, or can head into the interior of the castle, which is mainly a sunken airship.
Mario enters a Fishbone-infested pool, where it seems an underwater ruin exists. Mario must cross the path, which gets thinner and thinner as time wears on.