Inishmore Island, Ireland offers 1 beach perfect for sunbathing, surfing, swimming, and more. Inishmore Island is known for the ancient stone fort Dun Aonghasa and the dramatic cliffs of Aran. The best time to travel to Inishmore Island, Ireland, is from May to September, when the average air temperature is around 15-20°C (59-68°F) and the water temperature is approximately 12-16°C (54-61°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!