Open Water Swimming
Open Water Swimming Training Guide: From Pool to Lake, Bay, and Channel
How to train for open water swimming races — sighting, navigation, wetsuit swimming, cold water acclimation, and choosing a distance from 1K to marathon swims.
The open water difference
Open water swimming (OWS) is swimming in natural bodies of water — lakes, bays, rivers, oceans — without lane lines, walls, or clear water. The format ranges from 1K sprint events to marathon channel swims (21K or more). The sport demands swimming fitness, navigation skills, and the ability to handle cold, currents, waves, and marine life. For pool swimmers, the transition to open water is as much mental as physical — the lack of a black line and a wall can be disorienting, and the vastness of open water can be intimidating.
The rewards of open water swimming are significant: the freedom of swimming without turns, the beauty of natural settings, and the camaraderie of the OWS community. Most OWS races have kayak escorts and safety boats, making them safer than they appear. The sport is growing rapidly, with events from local 1K swims to iconic channel crossings. Browse open water swimming races to find events from 1K to marathon distance.
Sighting and navigation
Sighting — lifting your eyes out of the water to check your direction — is the core open water skill. In a pool, you follow the black line; in open water, you navigate to buoys, landmarks, or a compass bearing. The technique is to lift your head just enough to see forward, then turn to the side to breathe, all in one smooth motion. Practice sighting every 4 to 6 strokes in the pool, lifting your eyes every few lengths, so the motion becomes natural.
In a race, sight off the course buoys. Most OWS races mark the course with large, brightly colored buoys. Swim from buoy to buoy, sighting every 10 to 20 strokes to stay on course. Swimming off-course adds distance and time — a swimmer who veers 10 degrees off course can add 10 percent to their total distance. If you swim in a pack, you can draft behind another swimmer and let them do the sighting, but always verify the direction yourself. Use the race calendar to find an OWS race and practice sighting in the pool before the event.
Wetsuit swimming and cold water
A wetsuit is the most important piece of OWS gear. It provides buoyancy (lifting your legs and hips into a more efficient position), warmth (allowing you to swim in water that would otherwise be dangerously cold), and protection from jellyfish and debris. Wetsuits are legal in most OWS races when the water temperature is below 76 degrees Fahrenheit; above that, they are banned because they provide an unfair buoyancy advantage.
Swimming in a wetsuit feels different from swimming without one. The suit restricts shoulder range of motion slightly, so you may need to adjust your stroke. Practice swimming in your wetsuit before race day — a wetsuit that fits poorly or is worn incorrectly can cause chafing and restrict breathing. Apply anti-chafe balm to your neck and armpits before swimming. For cold water acclimation, start with short swims in cool water and build your tolerance gradually. Cold water shock is a real risk — never swim alone in cold water, and exit if you feel disoriented or excessively cold. Save your target OWS race to My Season so the countdown keeps your training on track.
Training for distance
OWS training volume depends on the target distance. A 1K race can be trained for with 3 to 4 pool sessions per week of 2,000 to 3,000 meters each. A 5K race demands more endurance — build to one long pool session of 4,000 to 5,000 meters per week, plus shorter quality sessions. A marathon swim (10K or more) demands significant volume: 5 to 6 sessions per week, with a total of 15,000 to 25,000 meters per week at the peak.
Open water practice is essential, not optional. Pool fitness does not fully transfer to open water because of the variables — wind, waves, current, temperature, and sighting. Swim in open water at least once a week in the months before a race, ideally in conditions similar to the race venue. If you do not have access to open water, practice sighting and swimming without turns in the pool (swim a length, turn around at the wall without pushing off, and continue). Browse open water swimming races to find events and check the water temperature and course profile.
Choosing your first open water swim
For a first OWS race, choose a 1K event in sheltered water (a lake or calm bay) with kayak escort and a water temperature above 65 degrees. Avoid ocean swims with waves or current for your first race, as the conditions add stress you do not need. Check the race's safety plan: kayak escorts, lifeguards, and a clear course with buoys. Use the race directory to filter by state and date, and look for beginner-friendly events.
Gear for a first OWS race: a wetsuit (if the water is cool), two swim caps (one bright for visibility), goggles with appropriate tint (clear for low light, tinted for bright sun), and anti-chafe balm. Bring warm clothes for after the swim, as you will be cold exiting the water. After your first OWS race, the natural progression is to longer distances — 2K, 5K, and eventually 10K marathon swims. The triathlon training guide covers the swim discipline in a multi-sport context.