World 1-1 is the first level of New Super Mario Bros. Wii and the first level of World 1. World 1-1 has Peach's castle on the background. It is similar to a tutorial level. Beating this will unlock World 1-2.
On Princess Peach's birthday, Peach invites Mario, Luigi, Yellow Toad, and Blue Toad. Suddenly, a giant cake appears with many hairs and customizations sticking out. Then, Bowser, Jr. and the Koopalings jump out. They then throw the cake on top of Peach, kidnapping her and knocking the heroes out. They then take the cake into Bowser's airship and leave the castle as the heroes follow them. Two Toads see this and blow out two cannons with propellor and penguin suits. Then, the airship will go to the tower and drop Larry off as the airship proceeds to the Castle.
At first, the players start off at a normal ground with 3 ? blocks. One of them contains a mushroom (or a propellor if multiplayer mode). Then, the player will see the first moving piece of ground and can enter a pipe filled with blocks, coins, and a P switch. Once they come out, they see 3 pipes and a brick block. Then, there are 3 more pipes and the checkpoint. There is a slope with 2 brick blocks and a ? block. On top of them is a star coin which is accessed with a propellor suit or a long jump. Then, the players can proceed to the red ring. If the players succeed, they will get a fire flower (if you don't have a propellor suit) or a 1up Mushroom (if you do have a propellor suit). Continuing on the platforms will lead to the third star coin. Then, the player must jump down on a moving piece of ground and will find 3 1ups (only if you find the secret pathway). There is also a pipe that leads to the second star coin. Then, the player can continue and find the pole.
- Star Coin 1: After the checkpoint, there are 3 blocks. On top of them is the star coin. The player must use a propellor suit or a long jump to reach it or a bounce.
- Star Coin 2: On the second moving piece of ground, the player must wait for a pipe. The player must enter the pipe and bounce off the underground pipes or use a propellor suit to get it.
- Star Coin 3: After the red ring, the player must continue on the platforms to eventually reach the last star coin.
- Koopa Troopa