Half Ironman Training Plan (Ironman 70.3)

I’ll be honest: the idea of a Half Ironman used to terrify me. Even now, as I prepare for my first sprint triathlon, I think about how I’ll eventually tackle the 1.2-mile swim, the 56-mile bike ride, and the 13.1-mile run. It feels massive—almost untouchable. But here’s the thing: big goals like this don’t happen overnight. For me, this is part of a longer journey. I’m starting small, training for a sprint triathlon now, and in a year or two, I’ll set my sights on an Ironman 70.3. After that? The full Ironman. It’s a dream I’m chasing, one sweaty workout at a time.

Let me walk you through what I’ve learned about Half Ironman training and what I’m planning for my future attempt.

Understanding the Monster

An Ironman 70.3 is no joke. You’ve got the distances:

• 1.2-mile swim (1.9 km): That’s like doing 20 laps in a standard pool without stopping.
• 56-mile bike (90 km): Imagine pedaling to the next city and back.
• 13.1-mile run (21.1 km): Oh, and finish it off with a half marathon, because why not?

What makes it tough isn’t just the distances—it’s putting them all together. My coach once called it “the ultimate test of stubbornness,” and that’s stuck with me. The first time I tried a “brick workout” (where you do two disciplines back-to-back), I was ready to quit after 5 minutes into the run. My legs were jelly, my heart felt like it was about to explode, and I was questioning why I even signed up for this triathlon life.

But here’s the magic: you get better. Each workout builds on the last, and suddenly, things that felt impossible are just… hard.

Training Plan: The Long Road to Preparedness

When I first thought about Half Ironman training, it overwhelmed me. I knew I couldn’t just wing it. So, I did what every aspiring triathlete does—I scoured the internet for plans, read books, and asked everyone who’d done a race for advice. What I pieced together is this:

Weeks 1-4: Base Building

This phase is all about laying the groundwork. You’re not aiming to break records; you’re building endurance and getting your body used to the grind.

• Swim: 2-3 sessions per week. Focus on technique. I love doing bilateral breathing drills because I tend to gasp for air after two laps.
• Bike: 2 sessions per week. Start with 90-minute rides at an easy pace and slowly add intervals to build strength.
• Run: 2-3 runs per week. Keep the pace conversational, and don’t stress about speed.
• Strength Training: Twice a week. Squats, planks, and stability exercises work wonders. I’ve noticed even in my sprint tri training that core work helps everything feel more connected.

Weeks 5-8: Building Strength and Volume

This is where it gets spicy. You’ll push your limits a little, but nothing too crazy.

• Swim: Add distance. Start swimming up to 2,000 meters per session. Open water is great if you can access it. My first open-water swim left me half-panicked—fish, waves, and no pool wall to grab onto.
• Bike: Increase your long rides to 3-4 hours. Include hills if your race course is hilly (or just for fun because hills are where mental toughness grows).
• Run: Build to 8-10 miles for your long runs. Add in one tempo session weekly.
• Brick Workouts: Weekly. Try a 90-minute bike ride followed by a 20-minute run. At first, your legs will feel like two rubber bands, but with time, it gets easier.

Weeks 9-12: The Final Stretch

This phase is about sharpening your skills and tapering so you feel fresh on race day.

• Swim: Focus on race pace and practice swimming with others if possible. I’ve heard the chaos of race-day swimming is no joke.
• Bike: Maintain fitness with shorter, high-quality rides.
• Run: Keep the runs shorter but mimic race intensity. I plan to cap my longest runs at 6 miles during this phase.
• Race Simulation: Do a mini triathlon. I plan to practice a 20-minute swim, 90-minute bike, and 30-minute run when I eventually train for a Half Ironman.

Fueling for Success

Nutrition is the silent killer—or savior—of your race. I learned this the hard way during a long ride where I didn’t pack enough snacks. By mile 40, I was bonking hard, barely able to push the pedals.

For an Ironman 70.3, you need a plan:

• Pre-race: Eat a carb-heavy meal the night before and a light breakfast.
• During the bike: Aim for 200-300 calories per hour. I’ve started experimenting with energy gels, bananas, and electrolyte drinks during longer training sessions.
• During the run: Stick with gels or chews, as solid food can mess up your stomach.

Pro tip: Never try new foods on race day.

What Keeps Me Going?

Whenever I get tired or frustrated, I think about the long game. The sprint triathlon I’m training for is just the beginning. A Half Ironman feels far off right now, but with every mile I swim, bike, or run, I’m building the foundation for that goal.

One thing I’ve learned: progress isn’t linear. Some weeks feel amazing, and others… well, let’s just say I’ve had my fair share of meltdown moments. Like the time I skipped a long run because I was “too tired” and then spent the rest of the day annoyed with myself. But you get back on the horse.

Final Thoughts

Training for an Ironman 70.3 isn’t just about the miles—it’s about discipline, patience, and learning to trust the process. If you’re on this journey too, know that you’re not alone. Celebrate the small wins, learn from the setbacks, and keep your eyes on the prize.

Because one day—maybe sooner than you think—you’ll cross that finish line, and every drop of sweat will be worth it. And after that? Well, there’s always the full Ironman calling your name. Let’s go.