Lady Elliot Island, a coral cay on the southernmost Great Barrier Reef, is a fantastic spot for observing sea turtles and other marine life. Green and hawksbill sea turtles feed, rest, and swim in the lagoon, sometimes venturing quite close to snorkellers; in the deeper waters off the island’s western side, you might witness manta rays sailing past or circling near coral outcrops that serve as cleaning stations.