Tropical Coast: Zone 4
Red Star Ring 1: When you land in the first non-spherical section of the zone, you'll see a bell. Chase the bell across a series of small platforms to unlock the first Red Star Ring.
Red Star Ring 2: During the side-scrolling section that makes up a healthy chunk of the level, you'll encounter five platforms elevated by water fountains. Ride the middlemost platform to the top, where a Red Star Ring awaits.
Red Star Ring 3: When you come to the second set of platforms elevated by water fountains, you'll see a loop immediately behind them. Using the homing attack on the flying enemy to reach the platform above the loop, where the Red Star Ring is waiting.
Red Star Ring 4: The fourth is easily found near the end of the level, between two monkeys throwing coconuts.
Red Star Ring 5: Near the end of the level, during an indoor segment in which spiky objects hang from the ceiling, the final Red Star Ring is found hovering high above the ground.