Open Water Distance Confidence Build: 45-Minute Progressive Swim

Session Overview

This 45-minute open water session is designed to progressively build your confidence and distance in lake or sea conditions. Ideal for intermediate triathletes preparing for a 1500m Olympic-distance swim, it uses a structured approach to build endurance while developing the mental resilience needed for race-day open water swimming.

What You’ll Need

• Triathlon wetsuit (mandatory in UK waters below 22°C)
• Swim buoy or tow float for safety (recommended for solo sessions)
• Swim cap (two caps for extra warmth in cold water)
• Triathlon goggles suitable for outdoor light conditions
• A buddy or lifeguard on shore — never swim alone in open water

Warm-Up (10 minutes)

Enter the water and acclimatise for 2–3 minutes — splash water on your face and neck before submerging to prevent the cold-water shock response. Then swim 300m at a very easy, comfortable pace (RPE 3–4). Focus on long, relaxed strokes and regular bilateral breathing.

Main Set

The main set builds distance progressively, with short rest intervals between each effort. If a buoy course is available, use it for distance measurement. Otherwise, estimate distance by swimming to a landmark and back.

• 300m: Steady effort (RPE 5), focusing on sighting every 8–10 strokes; rest 30 seconds
• 400m: Steady to moderate effort (RPE 6), maintain efficient stroke technique; rest 30 seconds
• 500m continuous: Race simulation effort (RPE 6–7), sight regularly, maintain pace throughout

Cool-Down (5 minutes)

Swim 200m at a very easy pace to bring your heart rate down before exiting the water. After leaving the water, change into dry clothes promptly, especially in cooler UK conditions, and drink a warm beverage to aid recovery.

Coaching Notes

• Sight more often in the first few hundred metres — nervousness tends to cause poor sighting and course deviation early in open water swims
• Focus on relaxed, rhythmic breathing rather than speed — staying calm is the most important skill in open water
• If you feel anxious, roll onto your back for a few strokes to rest and recalibrate — there is no shame in this and professionals do it too
• To progress: add 100m to the final continuous effort each week; work towards a continuous 1500m in subsequent sessions