Recreational diving offers many possibilities like guided liveaboard tours, independent dives with friends, technical diving, mountain lake diving, ice and cave diving with different equipment, but also free diving (Apnoe) as fun or competition as well as underwater sports competitions. Depending on the type of diving, there are various hazards which differ considerably from leisure activities in the dry. Diving medicine contributes to safety through preventive medical check-ups and consultations as well as assistance with unexpected problems and emergencies.