Pass through the Red Ring at Point 1, then jump to each of the nearby platforms to collect the red coins.
The ! Pipe at Point 2 contains a Mega Mushroom. This power-up allows you to collect the third Star Coin, but Mega Mario can cause serious damage to important areas. Unless you plan on revisiting this level, avoid using the ! Pipe until you’ve collected the first two Star Coins.
When you hit the ! Switch at Point 3, the Blocks below you swing apart and drop you right onto the first Star Coin. Dash to solid ground before the ! Switch wears off the and the temporary walkway vanishes.
The second Star Coin is located in a hidden area. Find the green pipe at Point 4, locate the Invisible Block just above it, then use the pipe to find the hidden area.
After you pass through the pipe, grab the Springboard and hop onto the platform to the right. As the platform moves back and forth across the gap, use the Springboard to bounce up to the Star Coin.
The third Star Coin is stuck in a small enclosure at Point 5. When you’re ready, return to the ! Pipe at Point 2, fill it with fireballs until the Mega Mushroom emerges, then use the power-up to clear a path to Point 5. Smash through the enclosure and collect the Star Coin before the Mega Mushroom wears off.