Open Water Tempo Swim: 4×400m at Race Pace

Session Overview

This session develops your ability to hold race pace in open water — one of the most transferable skills you can build before a triathlon. The 4×400m format lets you swim at genuine threshold effort while practising the sighting, breathing rhythm, and pacing that pool sessions can’t replicate. Best for intermediate swimmers targeting Olympic or 70.3 distances.

What You’ll Need

• Open water venue with a measured course or GPS watch for distance tracking
• Wetsuit (if water temperature is below 22°C)
• Safety swim buoy — mandatory for solo open water swimming
• GPS watch with open water swim mode
• Swimming partner or lifeguard supervision recommended

Warm-Up (10 minutes)

Swim 400m easy at conversational effort, focusing on long, relaxed strokes. Include 4–6 sighting reps every 10 strokes to practise lifting your head without breaking your rhythm. Spend the final 100m gradually increasing your stroke rate.

Main Set

Complete 4×400m at your target race pace (approximately RPE 7–8 out of 10). This should feel comfortably hard — you should be working, but not gasping. Take 90 seconds of easy swimming between each rep to recover fully before the next effort.

• Rep 1: 400m at race pace — focus on settling into rhythm in the first 50m
• Rep 2: 400m at race pace — practise sighting every 8–10 strokes
• Rep 3: 400m at race pace — push the second half slightly harder (negative split)
• Rep 4: 400m at race pace — race simulation, commit fully as if in a triathlon
• Recovery: 90 seconds easy swimming between each rep

Cool-Down (10 minutes)

Swim 400m very easy, focusing on technique rather than pace. Practise bilateral breathing (every 3 strokes) and use exaggerated hip rotation to loosen up. Exit the water slowly to give your body time to transition from horizontal to vertical without dizziness.

Coaching Notes

• Your first 50m of each rep will feel awkward — resist the urge to sprint out. Settle into pace within 30–40 strokes.
• Sighting in open water burns energy — keep your head low and look forward for just 1–2 seconds before returning to your normal stroke.
• If you don’t have a measured course, use a GPS watch set to open water mode. Target roughly 7:00–8:30 per 400m for most intermediate athletes.
• Make it easier: reduce to 3×400m. Make it harder: cut rest to 60 seconds or add a 5th rep.