24-Week Ironman Training Plan: Complete Guide

A 24-week Ironman training plan requires 12-20 hours of weekly training at peak, systematically building the endurance for a 3.8km swim, 180km bike, and full marathon.

Twenty-four weeks—six months—gives you enough time to build the aerobic base, develop race-specific fitness, and properly taper for your 140.6-mile journey. This guide provides the complete roadmap.

Plan Overview

Estimate your finish time: Ironman Time Calculator

Prerequisites

Before starting this plan, you should:

• Have completed at least one Olympic or Half Ironman distance
• Be able to train 10+ hours per week consistently
• Have a base of 6+ months consistent training
• Be injury-free and medically cleared

If you're a complete beginner, consider our First Ironman Complete Guide and the 36-week plan option.

Weekly Structure

Typical Training Week

Volume Progression

Phase-by-Phase Breakdown

Phase 1: Base Building (Weeks 1-8)

Goal: Build aerobic foundation across all three disciplines

Swim Focus:

• Technique emphasis
• CSS development
• 2,500-3,500m per session
• 2-3 sessions per week

Bike Focus:

• Zone 2 endurance
• Building to 3-4 hour rides
• 2-3 sessions per week
• Cadence work

Run Focus:

• Easy, conversational pace
• Building to 90-minute long run
• 3-4 sessions per week
• Form focus

Phase 2: Build Phase (Weeks 9-16)

Goal: Introduce race-specific intensity and longer sessions

Key Workouts:

Swim Threshold:

Warm-up: 400m easy
Pre-main: 4 x 100m build
Main: 5 x 400m at CSS pace, 30s rest
Cool-down: 200m easy
Total: 3,000m

Bike Tempo:

Warm-up: 20 min easy
Main: 3 x 20 min at 75% FTP
       10 min recovery between
Cool-down: 15 min easy
Total: 2:15

Run Tempo:

Warm-up: 15 min easy
Main: 3 x 15 min at marathon pace
       5 min recovery jog
Cool-down: 10 min easy
Total: 1:20

Phase 3: Peak Phase (Weeks 17-20)

Goal: Maximum volume, race simulation

Key Sessions:

• Long Bike: 5-6 hours at race effort with full nutrition practice
• Long Run: 2.5-3 hours at easy pace
• Race Simulation: Full bike + 1 hour run at race pacing
• Open Water Swims: 60-90 minutes with sighting practice

Phase 4: Taper (Weeks 21-24)

Volume Reduction:

Taper Principles:

• Reduce volume, maintain intensity
• Keep one quality session per discipline
• Focus on rest and recovery
• Dial in nutrition strategy

Learn more: Triathlon Taper Guide

Key Workouts by Phase

Must-Do Weekly Sessions

Swim:

• 1 x technique/drill session
• 1 x CSS threshold session
• 1 x endurance swim (build phase+)

Bike:

• 1 x interval/tempo session
• 1 x long ride (building to 5-6 hours)
• 1 x easy recovery spin

Run:

• 1 x interval/tempo session
• 1 x long run (building to 3 hours)
• 1-2 x easy runs

Brick:

• 1 x bike-to-run transition practice weekly

Ironman-Specific Training Elements

Long Course Considerations

Pacing Strategy:

• Swim: 70-75% effort, conserve energy
• Bike: 65-75% FTP, extremely conservative
• Run: Start slow, negative split if possible

Nutrition Training:

• Practice race nutrition every long ride
• Target 60-90g carbs per hour on bike
• Test multiple fueling strategies
• Train your gut

Mental Preparation:

• Break race into manageable chunks
• Develop mantras for low points
• Visualize race execution
• Practice positive self-talk

Sample Peak Week (Week 18)

Training Zones for Ironman

Bike Power Zones

Ironman race effort: 65-75% FTP

Find your FTP: FTP Calculator

Run Heart Rate Zones

Ironman marathon target: Zone 2-low Zone 3

Common Training Mistakes

1. Too Much Intensity

The Problem: Going hard too often The Consequence: Burnout before race day The Fix: 80% easy, 20% hard

2. Neglecting Nutrition Practice

The Problem: Only training fitness, not fueling The Consequence: GI issues on race day The Fix: Practice race nutrition every long session

3. Insufficient Long Sessions

The Problem: Never training race-duration The Consequence: Unknown how body responds The Fix: Build to 5-6 hour rides, 3 hour runs

4. Ignoring Recovery

The Problem: Not resting enough The Consequence: Overtraining, injury, illness The Fix: Recovery weeks every 3-4 weeks

5. Skipping the Taper

The Problem: Training through race week The Consequence: Arriving tired The Fix: Trust the 3-week taper

Adapting the Plan

For Time-Crunched Athletes (10-12 hrs/week max)

• Focus on key sessions
• Prioritize long bike and run
• Use indoor training for efficiency
• Accept slower race times

For Experienced Athletes

• Can handle higher volume
• More intensity tolerance
• Shorter adaptation periods
• Consider 20-week option

For First-Timers

• Add 4-8 weeks (28-36 week plan)
• Focus on completion, not time
• Build conservatively
• Consider: First Ironman Guide

Race Week Protocol

Final Week Schedule

Pre-Race Checklist

• Bike checked and tuned
• All nutrition prepared
• Race kit ready
• Transition bags packed
• Know the course
• Sleep strategy for race week
• Hydration plan

More details: Ironman Race Week Guide

Expected Results

Finish Time Ranges by Training Level

Related Resources

• Ironman Time Calculator - Predict your finish
• First Ironman Complete Guide - Everything you need to know
• Ironman Nutrition Guide - Race day fueling
• 30-Week Ironman Training Plan - Extended timeline
• Triathlon Periodization Explained - Training phases
• 16-Week Half Ironman Plan - Shorter distance prep