Star Coin 1: On an upward slope, with the pipe lying down, use the Yoshi and release the Yoshi to grab the Star Coin.
Star Coin 2: Among the four green pipes and the yellow pipe, go to the third pipe where the second Piranha Plant is from the left. move left and go inside the yellow pipe. Get the Star Coin in the air.
Star Coin 3: Go on the right-angled red pipe and jump to the right by hovering with the Yoshi.