Port Isabel, United States offers 4 beaches perfect for sunbathing, surfing, swimming, and more. Port Isabel is known for the Port Isabel Lighthouse, the Port Isabel Historical Museum, and the South Padre Island Dolphin Research & Sea Life Nature Center. The best time to travel to Port Isabel, United States, is from March to May, with average air temperatures ranging from 70°F to 85°F and water temperatures around 70°F to 75°F. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!