World 4-1 is a level found in the game New Super Mario Bros. Wii.
- Star Coin 1: Freeze the Pirahna underwater with the Penguin Suit, then jump on the frozen Pirahna to get the first Star Coin. This is located near the beginning of the course.
- Star Coin 2: Freeze the Urchin underwater with the Penguin Suit, then jump on the frozen Urchin to get the first Star Coin. You've got to hurry beforeit unfreezes! This is located slightly after the midway point.
- Star Coin 3: Belly slide on the water that has Urchins and pipes underneath. Then jump on the ledge. There is a pipe, but don't enter it yet! There is the third Star Coin waiting for you.