As you’re riding the first moving platform you’ll come to a section with Lemmy bouncing balls in it. You need to bounce off one of these balls to get to the upper area and get the Star Coin. Don’t waste too much time as the platform moves on with or without you.

As drop out of the next pipe you’ll see the Star Coin. You need to use the explosive power of the Bo-ombs to blow up the ice to get to the Star Coin.

As Mario rides the second moving platform just past the Midway Flag you’ll come to the final Star Coin on some of the drop platforms. Just grab the Star Coin and keep jumping until the platform gets back under you.

This time Lemmy’s ball gets bigger. So you just have to make sure you are getting good height off the bouncy balls so that you assure yourself Mario will land on Lemmy’s head. Do this 4 times. No, I’m kidding, do it 3 times.