The Tobago Cays are five small uninhabited islands ringed by a horseshoe reef, about eight nautical miles east of Union Island and part of a protected marine park. The shallow turquoise water inside the reef is one of the best snorkelling spots in the Caribbean: you can swim alongside hawksbill turtles, French angels, and spotted eagle rays without putting on scuba gear.
Day trips run from Clifton Harbour on Union Island, taking about 30 minutes by motorboat. Most trips stop at the turtle sanctuary at Baradal, then move on to a coral garden at Petit Rameau, and finish with a beach barbecue on one of the sandy spits. Bring your own food and water if you are going independently — the islands have no facilities. The reef is visibly healthier in the early morning before the day-trip boats arrive, so an early start is worth the effort.