Wounds sustained in oceans, lakes, and streams are exposed to a milieu of bacteria rarely encountered in typical land-based injuries. These include Vibrio species, Aeromonas hydrophila, Pseudomonas and Plesiomonas species, Erysipelothrix rhusiopathiae, Mycobacterium marinum, and other microbes. Failure to recognize and treat these less common pathogens in a timely manner may result in significant morbidity or death. Initial antibiotic therapy should address common gram-positive and gram-negative aquatic bacteria, depending on the environment. Trauma occurring in brackish or salt water should be treated with doxycycline and ceftazidime, or a fluoroquinolone (eg, ciprofloxacin or levofloxacin). Freshwater wounds should be managed with ciprofloxacin, levofloxacin, or a third- or fourth-generation cephalosporin (eg, ceftazidime). Injuries sustained in a marine or freshwater environment may result from bites or venomous stings of aquatic organisms as well as from accidental trauma. Musculoskeletal trauma caused by venomous underwater species (eg, stingrays, stinging fish, sea urchins, and coral) requires immediate neutralization of the heat-labile toxin with immersion in nonscalding water for 30 to 90 minutes. Appropriate management of aquatic wounds requires recognition of the mechanism of injury, neutralization of venom, antibiotic administration, radiographic assessment, surgical débridement with irrigation, wound cultures, and structural repair or amputation as indicated by the severity of the injury.