San Carlos, United States offers 8 beaches perfect for sunbathing, surfing, swimming, and more. San Carlos, Florida, United States, is known for its proximity to the beautiful beaches of Fort Myers and Sanibel Island. The best time to travel to San Carlos, United States, is in late spring or early fall when the average air temperature is around 70°F (21°C) and the water temperature is approximately 60°F (16°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!