Open-water swim training
Free Open-Water Swim Training Plan
Open-water swimming adds things the pool never asks for: no walls to rest on, no black line to follow, cold water, chop and a crowd. A good plan builds steady aerobic speed in the pool and practises those open-water skills safely outside it.
- Common distances
- 1.5 km, 3 km, 5 km and 10 km
- Typical build
- 8 to 16 weeks
- Swims per week
- 3 to 5, one in open water
- Taper
- 7 to 10 days
How an open-water swim plan is structured
A build for a 3 to 10 km swim usually lasts 8 to 16 weeks. Early weeks build technique and aerobic volume in the pool. The middle weeks add threshold sets at critical swim speed and longer continuous swims. The final weeks move more of the training into open water, rehearse race skills and taper. Weekly distance rises gradually, with a lighter week every three or four.
Find your CSS and train around it
Critical swim speed is your sustainable threshold pace. Swim a 400 m and a 200 m time trial with full rest between; CSS in metres per second is 200 divided by the difference between the two times in seconds. Most people convert it to a pace per 100 m. Sets like 10 to 20 × 100 m at CSS with 10 to 15 seconds rest are the core of distance swimming, and longer repeats such as 4 × 400 m build race-specific endurance.
Sighting, breathing and drafting
Sight every six to nine strokes by lifting your eyes just above the surface as part of the stroke, then breathe to the side. Practise in the pool by sighting a target at the end of each length. Bilateral breathing lets you cope with waves and sun on either side. Drafting just behind or beside another swimmer saves real energy, so practise swimming close to others before race day.
Cold water and safety
Cold water takes acclimatisation. Build exposure gradually over weeks, enter slowly, and expect your breathing to spike in the first minute; exhale steadily until it settles. Never swim alone in open water: swim with a group, a kayaker or at a supervised venue, wear a bright cap and use a tow float. Check your event's wetsuit rules, which depend on the water temperature and the governing body.
Long swims, feeding and the taper
Long continuous swims build toward about 70 to 80 percent of race distance for a 5 km, and 6 to 8 km for a 10 km. For swims over about 90 minutes, practise feeding: a carbohydrate drink or gel every 20 to 30 minutes, taken quickly on your back. Taper over 7 to 10 days, cutting distance by around 30 to 50 percent and keeping short CSS repeats to stay sharp.
A sample week
A build-phase week for a 5 km swim, about 14 to 16 km of swimming. With three swims, keep the CSS set, the open-water swim and one long pool swim.
- Mon
- Rest
- Tue
- Pool, 3.5 km: warm-up, 15 × 100 m at CSS, 15 s rest, easy cool-down
- Wed
- Pool, 2.5 km technique: drills, sighting every length, bilateral breathing
- Thu
- Pool, 3.5 km: 4 × 400 m at CSS plus 3 s per 100, 30 s rest
- Fri
- Rest or strength and mobility, 30 min
- Sat
- Open water, 45 to 60 min continuous with a group, sighting and drafting practice
- Sun
- Pool, 3 km long aerobic swim, steady
The mistake that ruins open-water races
Doing all the training in the pool. Pool fitness transfers, but sighting, cold, chop and a crowded start do not, and swimmers who meet them first on race day lose minutes swimming off course or panicking at the start. Get into open water regularly, safely, in the final two months.
Common questions
How long does it take to train for a 5K open-water swim?
Eight to sixteen weeks if you can already swim 1.5 to 2 km continuously. Newer swimmers should build pool volume and technique first.
What is CSS in swimming?
Critical swim speed, your sustainable threshold pace. It is calculated from a 400 m and a 200 m time trial and used to set pool interval paces.
How often should I swim in open water?
Once a week in the final six to eight weeks is a good minimum, always with a group, a support kayak or at a supervised venue.
Is the swim plan free?
Yes. AthleteSpace is free with no credit card, and it writes sets in metres or yards for the pool you swim in.