Great Thatch Island, British Virgin Islands offers 1 beach perfect for sunbathing, surfing, swimming, and more. Great Thatch Island is known for its uninhabited natural beauty and proximity to the popular snorkeling and diving site, The Indians. The best time to travel to Great Thatch Island, British Virgin Islands, is from December to April, with average air temperatures around 77-82°F (25-28°C) and water temperatures about 79-82°F (26-28°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!