Ironman 70.3: Master the Swim!

Wondering how to prepare for the 1.9 km swim leg of your Ironman 70.3?

Building strength, endurance, and open-water skills is critical if you want to exit the water confident and ready to conquer the bike and run.

Why Focused Swim Training Matters for Ironman 70.3

While the 1.9 km swim is a relatively short part of the race, it can make a big difference in your overall performance.

Strong swim fitness allows you to start the bike feeling fresh instead of drained. Training for Ironman 70.3 swimming means balancing endurance, pacing, technique, and open-water adaptability — not just raw speed.

These 10 key Ironman 70.3 swim sessions will help you sharpen your technique, boost your aerobic capacity, and set up a strong race day!

10 Essential Ironman 70.3 Swim Sessions

1. Long Endurance Swim

Purpose: Build aerobic capacity and mental stamina.

Warm-up:

400m easy

Main set:

3 x 800m at steady Zone 2 pace (30 sec rest)

Cool-down

200m easy

Focus: Maintain consistent technique and effort over longer distances.

2. Threshold Interval Swim

Purpose: Improve swim strength and sustainable speed.

Warm-up:

400m easy

Main set:

10 x 100m at CSS pace (Critical Swim Speed), 15 sec rest

Cool-down

200m easy

Focus: Hold strong pacing while maintaining good form under fatigue.

3. Race-Pace Swim

Purpose: Simulate race-day effort and breathing patterns.

Warm-up:

400m easy

Main set:

3 x 600m at race pace, 45 sec rest

Cool-down

200m easy

Focus: Practice pacing, breathing, and staying relaxed at race intensity.

4. Open-Water Skills Swim

Purpose: Prepare for race conditions including sighting and drafting.

Warm-up:

400m easy

Main set:

4 x 400m with sighting every 6 strokes (30 sec rest)

Cool-down

200m easy

Focus: Improve navigation and rhythm in open-water settings.

5. Strength & Power Swim (Paddles & Band)

Purpose: Build upper-body strength and core stability.

Warm-up:

400m easy

Main set:

• 6 x 100m with paddles and pull buoy (20 sec rest)

• 4 x 50m with ankle band (30 sec rest)

Cool-down

200m easy

Focus: Strengthen pull mechanics and streamline body position.

6. Sprint Speed Development

Purpose: Boost start speed and fast-twitch muscle response.

Warm-up:

400m easy

Main set:

12 x 50m at 90% effort (30 sec rest)

Cool-down

200m easy

Focus: Deliver controlled speed bursts without sacrificing form.

7. CSS Pacing Control Swim

Purpose: Train even pacing and aerobic endurance.

Warm-up:

400m easy

Main set:

4 x 300m at CSS pace (30 sec rest)

Cool-down

200m easy

Focus: Stay consistent and efficient throughout longer swims.

8. Broken Race Simulation Swim

Purpose: Replicate race fatigue and effort changes.

Warm-up:

400m easy

Main set:

3 x (300m at race pace + 100m hard) (30 sec rest)

Cool-down

200m easy

Focus: Prepare for accelerations and transitions under race conditions.

9. High-Turnover Technique Swim

Purpose: Improve stroke rate and maintain efficiency.

Warm-up:

400m easy

Main set:

• 4 x 100m focusing on high stroke rate (20 sec rest)

• 4 x 50m descending effort (each faster) (30 sec rest)

Cool-down

200m easy

Focus: Increase turnover without losing control or efficiency.

10. Taper Speed & Efficiency Swim

Purpose: Maintain sharpness and confidence before race day. (7–10 days before race):

Warm-up:

400m easy

Main set:

• 4 x 200m at CSS pace (30 sec rest)

• 6 x 50m at race effort (30 sec rest)

Cool-down

200m easy

Focus: Feel fast, relaxed, and fully prepared for race conditions.

Final Tips for Ironman 70.3 Swim Success

• Practice Fueling: Longer swims still demand proper hydration and fueling habits.

• Open-Water Practice: Simulate real race conditions whenever possible.

• Stay Consistent: Regular swim training leads to greater efficiency and pacing control.

FAQs About Ironman 70.3 Swim Training

How many times per week should I swim for Ironman 70.3?

Most athletes benefit from 3–4 swim sessions per week, balancing endurance, pacing, and technique.

What is a good swim pace for Ironman 70.3?

Aim for a sustainable pace where you can breathe rhythmically — typically around 70–80% of threshold effort.

Is open water swimming necessary before my race?

Yes — even one or two open water sessions can dramatically boost confidence and skills.

Final Thoughts

The Ironman 70.3 swim is your opportunity to start the race strong, confident, and ready to perform.

Which swim session will you focus on first to build your endurance, speed, and open-water confidence?

Always consult with a medical professional or certified coach before beginning any new training program. The information provided is for educational purposes only and is not a substitute for personalized advice.