New Super Luigi U: Acorn Plains-3 -- Rolling Yoshi Hills

There are rolling hills here, which affect your speed. Monty Moles will pop out of the rocks, so keep an eye out for them. Throw a Koopa shell to the right, under a ledge, to get the first Star Coin. Nearby, you'll find a couple of item blocks, one with a Yoshi in it. To the right are hidden alcoves with coins. There's a low platform with lots of Piranha Plants. Use a shell on the other side of the gap to clear them out so you can get the second Star Coin. Up ahead are a couple of POW Blocks so you can get the coins in the sky. The third Star Coin is just in front of the flagpole. Use Yoshi or a POW Block to get it.