Take a kaito boat from Sai Kung pier (HK$30 round-trip, 15 minutes) to Sharp Island. The water here is actually clear enough for decent snorkeling, which is rare this close to Hong Kong.

Best spot is Half Moon Bay on the island's north side. Bring your own gear — There's no rental on the island. The tombolo (land bridge) to Kiu Tau appears at low tide, which is worth timing your visit around.

Boats run regularly but check the weather. Rough seas cancel service. Pack water and snacks — There's only one small shop on the island.