We offer a range of solutions for snorkelers needing plus (long sighted), minus (short sighted) and bifocal lens. We have solutions for new masks but also options to fit to existing masks. Prescription snorkel masks offer snorkelers clarity underwater. We offer corrective lenses for long, short and bifocal prescriptions. If your prescription is between the strengths shown then select the weaker as the water offers some magnification. Not sure exactly what you require? Read about choosing a prescription mask and watch our video on how to change lenses if you want to do this yourself, otherwise we are happy to fit them for you.