How to apply sunscreen before swimming

  1. 1Check the bottle for broad spectrum protection, SPF 30 or higher and water resistance. On US labels, look for a water resistance duration of 40 or 80 minutes. Read the application directions for your particular sunscreen.
  2. 2Apply generously at least 15 minutes before going outdoors. Do not wait until you are already in the sun to start applying.
  3. 3Cover every area not covered by clothing and rub sunscreen in thoroughly. Most adults need about one ounce to cover exposed skin, with more needed depending on body size. For the face, use at least one teaspoon.
  4. 4Include your ears, neck, legs and tops of your feet. Ask someone to help cover your back. Use SPF 30 or higher lip balm, and protect an exposed scalp with sunscreen or a hat.
  5. 5Take the sunscreen with you for reapplication, but keep the container shaded or wrapped in a towel rather than sitting in direct sun.
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The word "sport" is not a defined sunscreen standard, so the athletic branding does not do the label reading for you. Check the water resistance claim instead.6

How often should I reapply sunscreen while swimming?

Follow the bottle's 40 or 80 minute water resistance limit while swimming or sweating. If you are still swimming when that limit arrives, get out and reapply. Once you finish a swim, reapply straight away, even if the sunscreen is water resistant. Reapply after towel drying too, because rubbing can remove sunscreen. The two hour rule applies when you are outdoors between swims; it does not override an earlier water resistance limit or towel drying.36

Does sunscreen wash off in water?

Yes, all sunscreens eventually wash off. Water resistant sunscreen is tested to remain effective during water exposure for the duration printed on its label. There is no waterproof sunscreen, even if the name sounds ready to cross an ocean. Water also reflects ultraviolet rays, increasing exposure, while its cooling effect can hide the feeling that you are burning. Feeling cool is not a useful measure of sun protection.35

What SPF should I use at the beach?

Use SPF 30 or higher with broad spectrum protection and water resistance. SPF describes protection against sunburn, mainly from ultraviolet B rays, or UVB. Broad spectrum protection also covers ultraviolet A rays, or UVA. For UK sunscreen labels, look for at least four star UVA protection; UVA in a circle indicates the EU standard. Higher SPF provides greater sunburn protection, but it does not buy a longer interval between applications. No sunscreen filters out all UVB rays.356

Between swims, use shade and clothing as well as sunscreen. Do not extend your time in the sun because you are wearing sunscreen. If you are swimming somewhere with restrictions on sunscreen ingredients, check the current local rules. "Reef safe" has no FDA definition, and the effects of sunscreen ingredients on reefs remain uncertain.367

Who needs extra care?

For sensitive skin, consider a mineral sunscreen containing zinc oxide or titanium dioxide, while still checking SPF, broad spectrum protection and water resistance. Keep babies under six months out of direct sunlight and ask a doctor before applying sunscreen. Do not apply sunscreen to damaged or broken skin, and stop using it and ask a doctor if a rash occurs. If sunburn causes severe swelling, blisters or feeling unwell, seek medical help.3456

Where this answer comes from

  1. 1Water Safety (Recreational): MedlinePlusmedlineplus.gov
  2. 2How to apply sunscreenaad.org
  3. 3Sunscreen and sun safetynhs.uk
  4. 4Labeling and Effectiveness Testing: Sunscreen Drug Products for Over-The-Counter Human Use — Small Entity Compliance Guidefda.gov
  5. 5Sunscreen: How to Help Protect Your Skin from the Sunfda.gov
  6. 6How to decode a sunscreen labelaad.org
  7. 7Sunscreens: A Complete Overviewdermnetnz.org