Related Clues:

• Underwater ridge
• Scuba spot
• Home to some mollusks
• Backdrop for some schools
• Bikini or Eniwetok
• Natural barrier
• Repurposed shipwreck
• Lagoon-enclosing isle
• Coral reef formation
• Leading character's sound as a bell in The Coral Island
• Bikini, perhaps, shown to everyone around
• A charge to go across an island?
• Bikini, say, visible to everyone around
• A charge for crossing island
• Bikini has a high price