Le Diamant, France offers 4 beaches perfect for sunbathing, surfing, swimming, and more. Le Diamant is known for the iconic Diamond Rock, a striking volcanic island off its coast. The best time to travel to Le Diamant, France, is from December to April, with average air temperatures around 27°C (81°F) and water temperatures about 26°C (79°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!