Gujan Mestras, France offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Gujan Mestras is known for its picturesque oyster ports and the Parc de la Coccinelle. The best time to travel to Gujan-Mestras, France, is from June to September, with average air temperatures ranging from 20°C to 25°C (68°F to 77°F) and water temperatures around 18°C to 22°C (64°F to 72°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!