Osteoporosis is a metabolic bone disease that causes variations in the bone microarchitecture, compromising its strength and quality. Osteoporosis affects 30 million people in Europe, mainly postmenopausal women. Exercise positively influences bone mineral content and is a central element in the prevention and treatment of the disease. Exercise on land seems the most suitable for this purpose; however, water exercise, in particular conditions, can be a valid and safe treatment alternative.