All coastal states must provide telemedical assistance services (TMAS) 24 h a day free of charge to all ships. Skin lesions account for many urgent TMAS consultations, but may be difficult to describe for seafarers without much medical training - and even for medical personnel on cruise ships. By following simple instructions provided in this article, good photographs - taken by digital cameras or smart phones and transmitted by e-mail to TMAS - can compensate for imprecise descriptions. The on-line TMAS physician can then easily consult with a dermatologist if necessary. Highly specialised teledermatology services are commercially available for cruise companies. Their ship's doctors thereby get prompt access to expert medical opinion without the time, logistical issues and costs associated with seeking dermatologic care ashore. Teledermatology allows cruise medical staff to effectively manage skin conditions aboard and limits unnecessary dermatology clinic referrals. For the ships' medical staff the teledermatology service is also an opportunity for continuous education which may benefit skin patients aboard in the future.