New Super Mario Bros./World 3

World 3-1
Slide down the pipe to start the level. The first Star Coin is past the checkpoint. When you see a red pipe next to two green pipes, head down the middle pipe. Swim to the right, grab the Star Coin, and go out the pipe on the right. For the second Star Coin, wait until the big fish starts heading towards the right, and grab it. To make the third Star Coin easier to grab, hit the switch. If you don't, you can always destroy the blocks, but the fish might get you when you grab the coin. Swim as fast as you can and head up the pipe to finish the level.

World 3-A
Head right. Past the checkpoint, hit the red switch in the water to make blocks appear and continue. In the next water hole, go down and let the water-glider destroy blocks to access the first Star Coin. Get out of the water and head right. Run and jump from the first barrel to reach the second Star Coin. Go through the green warp pipe. If you are Mini Mario or have a Mini Mushroom go in the overhead green warp pipe and grab the third Star Coin by running over the water and jumping. Go out the green pipe on the right, and finish the level.

World 3-2
Head right, and when you hit the checkpoint, go down the yellow warp pipe. Grab the first Star Coin and head out the green warp pipe. Head across the balancing platforms and jump to the second Star Coin. If you head into the green pipe when you get on the moving mushroom, you can get a lot of coins and it leads to the alternate exit, which leads to World 3-B. Otherwise, keep heading right. Grab the third Star Coin when the mushroom is extremely tilted and finish the level.

World 3-Tower
Go down the middle pipe to be launched up. Grab the grid by pressing up. You can destroy things on the opposite side by pressing the Dash button or jump up to the next one by pressing Jump. Let yourself fall to the last, big grid and go left and up. Wall-jump to grab the first Star Coin. Fall down to the bottom and launch yourself up. This time, grab the uppermost grid and climb. To flip sides, press the Dash button. Go up on the right and flip the grid to come back to the forefront. Destroy the two columns of blocks and go left to grab the second Star Coin. From the coin, go back to the flip, go right and up to the door. Hit the red switch and climb quickly to the door and the third Star Coin. Go through, and then climb up to the left to go through the double doors to Bowser Jr. Destroy Bowser Jr. by jumping on him.

World 3-B
Head right until you come across a red warp pipe that is by itself, below an overhanging red pipe. Go left and up the red pipe on the left side. Grab the first Star Coin, go back down, right, and up. For the second Star Coin, head right slightly and wall-jump between the red pipe and the green pipe to go right and grab the coin. Let yourself down and continue right. Grab the third Star Coin and finish the level.

World 3-3
Head down the green pipe to start this underwater level. Head right until the second yellow pipe. Head down and grab the first Star Coin to the left. Hit the switch by sinking to it, head back up and left, go down on the right where the jets have stopped. In the area with lots of pipes, head down the third one. Go to the bottom right corner to grab the second Star Coin. The exit is in the top right corner. Allow yourself to be pushed up and right. All the way at the right, let yourself sink to the third coin. Come back to the overhead green warp pipe quickly to avoid the Bloopers and finish the level.

World 3-C
When you see the first Star Coin, stand above it on the platforms to fall to it. Jump back up quickly to avoid the big fish. When you go for the second Star Coin from underneath, be careful to avoid the big fish as well. Hit the switch and hurry to the right to go into the red warp pipe. This will drop you onto the third Star Coin, and you can now finish the level.

World 3-Ghost House
Hit the orange switch to make stairs appear, which you can climb to continue. Skip the first door and head to the second, where you can jump on top of a pumpkin to grab the first Star Coin. Exit and hit the switch as the platform nears the bottom of its path. Climb the stairs, then jump onto the staircase on the left and go get the second Star Coin. Go back and hit the switch and this time climb all the way to the right. Now you have an opportunity for an alternate exit which leads to World 3-Cannon. Hit the block you see from underneath and then hit the switch. Go back to the previous switch and go through the new door (between the old door and the switch). Finish the level for the alternate path. Otherwise, hit the switch, climb the staircase, fall down, and go through the new door. For this third coin, you need to be Shell Mario. It is possible to get one by climbing on the left and hitting the block. Otherwise, use a Red Mushroom Shop. Once you are Shell Mario, run forward (jumping where necessary), and slide up the staircases to destroy the blocks all the way on the right. Grab the third Star Coin and head through the door to finish the level.

World 3-Cannon
Climb in the cannon to travel to World 6.

World 3-Castle
Head right, and when the spiked column is up, run under to grab the first Star Coin. To get out, wait until it goes back up. Next, continue and be careful of the suicidal slabs of concrete (they're just begging to be killed when they fall down like that). Go up the pole and get off on the right. Run across the yellow blocks and grab the rope. Swing yourself and release at the left to run left and above the ceiling. Drop down to grab the second Star Coin. Go back to the rope and release yourself on the right. When you reach the double doors, run, and duck just as you reach the wall to go underneath. Wait in the water for the opportune moment and grab the last Star Coin. Go back to the double doors and go in to meet the boss, the Big White and Purple Fish with Yellow Fins. To defeat him, jump on him three times. Beware of the small fish.