Nelsons Island, British Indian Ocean Territory offers 1 beach perfect for sunbathing, surfing, swimming, and more. Nelsons Island is known for its pristine beaches and unique wildlife in the British Indian Ocean Territory. The best time to travel to Nelsons Island, British Indian Ocean Territory, is from May to October, when the average air temperature is around 27°C (81°F) and the water temperature is approximately 28°C (82°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!