Unawatuna, Sri Lanka offers 5 beaches perfect for sunbathing, surfing, swimming, and more. Unawatuna is known for its picturesque Unawatuna Beach and the nearby Rumassala Sanctuary. The best time to travel to Unawatuna, Sri Lanka, is from December to March, with average air temperatures around 27°C (81°F) and water temperatures about 28°C (82°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!