Surfers' ear is a condition where bony growths (exostoses) grow in the ear, gradually closing the ear canal over and resulting in progressive deafness and increased risk of otitis externa ear infection. It is caused by the wind and sea water cooling the ear and the mastoid bone, the hard lump behind your ear. Many surfers mistakenly believe that they are only at risk in the winter when the air and sea temperature is lower but this is not the case. In fact, in the winter the risk is significantly reduced as many surfers wear a neoprene cap which protects the ears and the mastoid bone from the wind and cold water. Even though it is warmer in the summer the risk is still present as the wind causes accelerated evaporation of sea water from wet ears, cooling them and causing the body to respond by closing the ear canals over with bony growths. It is common for surfers who surf a particular coastline to suffer more in a particular ear due to the common direction of the wind in the area.

Many surfers who know about surfers' ear believe that ear plugs are enough to prevent it but this is not the case due to the effect of the cold on the mastoid bone; it is essential to wear a neoprene surfers' cap pulled down low over the ears, as well as a well fitting pair of surfing ear plugs.

Ear infection is more likely in surfers' ear as the ear canal is unable to dry out properly due to the narrowing caused by the bony exostoses. This results in reduced air flow in the ear canal, prolonged waterlogging and penetration of the protective wax and skin (squamous epithelium) lining the ear canal. This allows bacteria to infect the canal and cause swimmers' ear (otitis externa).

Infections can be challenging to deal with as the ear canal is often full of debris and tough to get antibiotic drops into due to narrowing. Therapy consists of drilling or chiselling the bone away to reopen the ear canal; this may be painful and very unpleasant. Unfortunately this is sometimes necessary after only a few years of frequent surfing. It is important to know that it can recur and sometimes surfers need the procedure repeating if they do not protect themselves from risk.

Avoidance of surfers' ear is far better than treatment. Putting on surfers' ear plugs and a hood stops wind and water entering the ears and shields the mastoid, ceasing development of the disease. Ear plugs for surfing have to be non-porous and are ideally antibacterial to help reduce the chance of infection from grimy sea water and dirty fingers. Surfers commonly use adhesive putty to prevent surfers' ear and swimmers' ear but it may fragment in the ear canal and need to be removed by a medical practitioner. Colourful ear plugs for surfing are simpler to find when you drop them on the beach or on the floor of your camper van and if you connect them with a cord you can tie them to the zip on your wetsuit so you don't lose them if they come out in the sea.

Prevent surfers' ear by wearing ear plugs and a cap all year round to protect hearing and avoid surgical treatment.