Event programsSwimming

10 km Open-Water Swim: 16 weeks, peaks at ~7 h.

The marathon swim: 10 km in open water, decided by lactate threshold, even pacing and feeding on the move — often against a 4–5 h cut-off. That's the intermediate plan; beginner runs 20, advanced runs 12 weeks.

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Written for where you are.

Beginner

20 weeks, 4 swims a week: the long swim from 3 to 8 km, feeds from week 5, open water from week 7, a 2-week taper.Shortest runway 15 weeks · research minimum 16 · 6 sources

20 wk

2.5-5.5 h a week

Intermediate

16 weeks, 5 swims a week: Red Mist through the build, an 8 km dress rehearsal in week 10, 9 km at race pace +2 s three weeks out.Shortest runway 12 weeks · research minimum 12 · 5 sources

16 wk

3-7 h a week

Advanced

12 weeks, 6 swims a week: CSS sets up to 40×100, open-water swims to 9 km, an optional full 10 km three weeks out.Shortest runway 7 weeks · research minimum 8 · 5 sources

12 wk

3.5-9 h a week

The checklist comes with it.

T-28Men over 40, or anyone with heart risk factors: get a pre-participation check. Two-thirds of US triathlon race deaths happened in the swim, mostly men over 40, often with hidden heart disease (Harris 2017).

T-7Water temperature and the wetsuit rule: World Aquatics races need ≥ 16 °C and make wetsuits compulsory below 18 °C. Cold shock is ~1 min of gasping, then swim failure within ~10 min — enter slowly and control your breathing.

T-7Goggles: one clear and one tinted pair, plus a spare. Anti-chafe.

T-3Course map: sighting landmarks and buoy colours. Start format (seeded, rolling or mass) — self-seed honestly. Know the exit and the safety craft.

race morningWarm-up swim of 10 min with 4×1 min at race pace, then a seeded or rolling start.

race morningCough, frothy or bloody sputum, or breathlessness in the water (SIPE): stop, signal the safety craft, exit and get medical care. Never swim open water alone.

T-7The feed plan and the pontoon or kayak arrangement; cap colour for your support crew.

T-7Test-drink the race product. Sunscreen; nipple and neck anti-chafe.

T-2Feed bottles pre-mixed, numbered and marked by time; a thermos for warm feeds below ~20 °C.

T-1Support-kayak briefing. Lanolin or anti-chafe for cold water.

race morningKnow the hypothermia pull-out criteria: slurred speech, stroke-rate collapse, confusion. Check the event's cut-off (often 4–5 h).

Every plan cites its homework.

Feeding for 2 h+ rests on general endurance guidance; one elite 10 km training study found no pace effect from 60 g/h (PMC6316724). Long cold swims can drop core temperature below 35 °C within an hour even in cold-adapted swimmers (Roxburgh 2026). Finish-time bands are dossier estimates.

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