Isla Water Cay, Nicaragua offers 1 beach perfect for sunbathing, surfing, swimming, and more. Isla Water Cay, South Caribbean Coast, Nicaragua, is known for its pristine beaches and vibrant coral reefs. The best time to travel to Isla Water Cay, Nicaragua, is from December to April, with average air temperatures around 85°F (29°C) and water temperatures near 82°F (28°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!