Pigeon Island Marine Park near Trincomalee is the standout snorkelling destination in Sri Lanka – a coral reef of genuine quality with reef sharks, parrotfish, and marine turtles in water so clear it’s almost disorienting. Hikkaduwa’s National Park reef is accessible and good for wildlife encounters with nesting turtles. Unawatuna’s sheltered bay is ideal for beginners and casual snorkellers looking for a beautiful reef experience without the effort.