Beginner’s Training Plan for an Ironman 70.3

1 day ago
3 min read

If you’re thinking about signing up for your first Ironman 70.3—first of all, do it. There’s nothing quite like the energy, the challenge, and the feeling of crossing that finish line.

But let’s be real: training for a 70.3 (1.2 mile swim, 56 mile bike, 13.1 mile run) can feel overwhelming, especially if you’re new to the sport. The key is having a structured plan that builds gradually, balances effort, and fits your life.

My first 70.3 since 2018 is this summer, so I have even needed a refresher on how to adjust my training. In fact, longer course training calls for a lot more “easy” workouts than I’ve been doing for Sprints and Olympics.

This guide breaks down a beginner-friendly training approach, including phases, weekly structure, and how to think about effort levels—while leaving room for flexibility.

The Big Picture

Most beginner 70.3 training plans span 14–18 weeks and follow a simple progression:

Build consistency first
Then build endurance
Then sharpen for race day

You’ll typically train 5–6 days per week, with a mix of:

Swim
Bike
Run
Strength
Recovery

Training Phases

1. Base Phase (Weeks 1–6)

Goal: Build consistency and aerobic endurance

This is where you lay the foundation. Nothing flashy—just showing up and getting comfortable with all three disciplines.

Focus:

Easy, steady efforts (Zone 2)
Shorter workouts
Good technique (especially in the swim)
Establishing routine

Sample Week:

Swim (easy): Technique + drills
Bike (easy): 45–60 min steady
Run (easy): 30–45 min conversational pace
Strength (moderate): 1–2 sessions
Long Bike (easy): 60–90 min
Long Run (easy): 45–60 min
Rest Day

👉 Effort guidance: ~80–90% of your training here should feel easy. You should be able to hold a conversation during most sessions.

2. Build Phase (Weeks 7–12)

Goal: Increase volume and introduce intensity

Now we start to layer in some structured “hard” efforts while extending endurance.

Focus:

Longer long workouts
Introduce intervals (tempo, threshold)
Add race-specific training

Sample Week:

Swim (moderate): Endurance + some faster intervals
Bike (hard): Interval session (e.g., 4x5 min at tempo)
Run (easy): Recovery run
Strength (moderate): 1–2 sessions
Brick (moderate): Bike + short run off the bike
Long Bike (easy–moderate): 90 min–2.5 hrs
Long Run (easy): 60–90 min

👉 Effort guidance:

~70–80% easy
~20–30% moderate to hard

“Hard” sessions should feel challenging but controlled—not all-out.

3. Peak Phase (Weeks 13–15)

Goal: Simulate race conditions and build confidence

This is where your longest and most race-specific sessions happen.

Focus:

Race pace efforts
Longer bricks
Dialing in nutrition and hydration

Sample Week:

Swim (moderate): Continuous effort or race simulation
Bike (hard): Race pace intervals
Run (moderate): Tempo efforts
Brick (hard): Longer bike + 20–30 min run
Long Bike (moderate): 2.5–3.5 hrs
Long Run (easy–moderate): 75–105 min
Rest / Recovery Day

👉 Effort guidance:

This phase includes your hardest sessions, but easy days are still easy. Recovery becomes just as important as the work.

4. Taper Phase (Weeks 16–18)

Goal: Arrive at the start line fresh and ready

You’ll reduce volume but keep a touch of intensity to stay sharp.

Focus:

Cutting back training time
Maintaining rhythm
Prioritizing sleep and recovery

Sample Week:

Shorter versions of all disciplines
A few brief race-pace efforts
Extra rest days

👉 Effort guidance:

Nothing should leave you exhausted. You should start to feel itchy to race.

Easy vs. Hard: How to Know the Difference

One of the biggest mistakes beginners make is going too hard, too often.

Easy Efforts:

Conversational pace
Low heart rate
Feels sustainable for a long time

Moderate Efforts:

Slightly uncomfortable
Focused but controlled
Used for tempo work

Hard Efforts:

Challenging and requires focus
Used for intervals or race pace
Should be balanced with recovery

💡 Rule of thumb: If everything feels “kind of hard,” you’re probably overdoing it.

Make It Your Own

This is a guideline, not a one-size-fits-all plan.

For example, I personally adjusted my training to:

Include at least 2 strength sessions per week
Do only one swim per week, since I come from a swimming background
Only have the long sessions on the weekends, as my work days usually start on the earlier side

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