Stay away from the rays
UVA and UVB rays are present both indoors and outdoors and are harmful to the skin. Combat them by applying an effective sunscreen before going out and reapply every two hours or as soon as you get out of the water.
If you lay under the sun, wear clothing that covers you well and bring a hat. Favour broad-spectrum sun protection adapted to your activity and your needs - cream, spray, stick, etc. - whether you run the trails or sail the water.