First Marathon Training Plan: 12 Weeks from 10K to Full Marathon

Decided to sign up for your first marathon? Congratulations! The full marathon (42.195 km) is one of the most important milestones for any runner. This plan is designed for runners who can already complete 10K and run 3 to 4 times per week, guiding you to safely finish a full marathon in 12 weeks.

1. Prerequisites

Before starting this plan, please confirm that you meet the following criteria:

• Can run 10 km continuously without walking
• Current weekly training volume of 30 to 40 km or more
• No unresolved running injuries
• At least 12 weeks of preparation time before race day

If you can currently only run 5 km, it is recommended to build up for 3 to 4 months before starting this plan.

2. Training Principles

The 10% Rule

Do not increase your weekly mileage by more than 10% over the previous week, to avoid overtraining.

The Long Run Is the Core

The weekend long run is the most important workout in marathon preparation. The longest run of each week gradually extends, peaking at 35 km.

A Recovery Week Every 4 Weeks

Weeks 4, 8, and 12 are cutback recovery weeks, with mileage reduced by 30% to let your body adapt and strengthen.

3. 12-Week Training Plan

Weeks 1-4: Building the Base

Week	Monday	Wednesday	Friday	Sunday (Long Run)	Weekly Mileage
Week 1	Easy run 8km	Speed run 10km	Easy run 8km	Long run 18km	44km
Week 2	Easy run 8km	Speed run 10km	Easy run 8km	Long run 21km	47km
Week 3	Easy run 8km	Tempo 10km	Easy run 10km	Long run 24km	52km
Week 4 (Recovery)	Easy run 6km	Easy run 8km	Easy run 6km	Long run 16km	36km

Weeks 5-8: Building Endurance

Week	Monday	Wednesday	Friday	Sunday (Long Run)	Weekly Mileage
Week 5	Easy run 8km	Intervals 10km	Easy run 10km	Long run 27km	55km
Week 6	Easy run 8km	Tempo 12km	Easy run 10km	Long run 29km	59km
Week 7	Easy run 10km	Intervals 12km	Easy run 10km	Long run 32km	64km
Week 8 (Recovery)	Easy run 6km	Easy run 8km	Easy run 6km	Long run 19km	39km

Weeks 9-12: Peak and Taper

Week	Monday	Wednesday	Friday	Sunday (Long Run)	Weekly Mileage
Week 9	Easy run 10km	Tempo 12km	Easy run 10km	Long run 35km	67km
Week 10	Easy run 8km	Intervals 10km	Easy run 8km	Long run 29km	55km
Week 11	Easy run 6km	Easy run 8km	Easy run 5km	Long run 19km	38km
Week 12 (Race Week)	Easy run 5km	Easy run 3km	Rest	Race Day	-

4. Workout Type Explanations

Easy Run

• Pace: 60 to 90 seconds slower than your marathon goal pace
• Heart rate: 60-70% of max heart rate
• Purpose: Recovery, aerobic base

Tempo Run

• Pace: 15 to 30 seconds faster than your marathon goal pace
• Heart rate: 80-85% of max heart rate
• Purpose: Raise lactate threshold

Interval Training

• Distance: 400m × 8, 800m × 5
• Intensity: 90% of full effort
• Rest: 2 minutes of easy jogging between reps

Long Run

• Pace: 60 to 120 seconds slower than your marathon goal pace
• Focus: Cover the distance, not the speed
• Fueling: Take an energy gel every 45 minutes

5. Common Mistakes First-Time Marathoners Make

1. Running the long run too fast → The purpose of the long run is time on your feet, not speed
2. Skipping recovery weeks → Recovery weeks are not slacking off; they are part of the plan
3. Increasing training volume two weeks before the race → The taper must be strictly followed
4. Skipping fueling practice → Practice fueling during long runs; do not try it for the first time on race day
5. Wearing new shoes on race day → Race shoes should have at least 100 km on them before you race

6. Gear Checklist

• Running shoes: Have at least two pairs and rotate them; avoid using the same pair consecutively
• Heart rate monitor: Track training intensity
• Running vest/belt: Carry fuel during long runs
• Compression calf sleeves: Reduce muscle vibration
• Anti-chafe balm: Inner thighs, nipples, armpits

7. Post-Race Recovery

A marathon takes a heavy toll on the body. After finishing, it is recommended to:

• Week 1: Complete rest or easy walking
• Weeks 2-3: Short, easy jogs
• From Week 4: Gradually return to normal training

Follow this plan, and you will cross the marathon finish line in 12 weeks. What matters is not your time, but finishing safely. Good luck with your first marathon!

Related Reading

• First Marathon 20-Week Training Plan: A Complete Framework from 10K to Full Marathon
• First Full Marathon Finish Guide: A 16-Week Roadmap
• First Marathon 16-Week Training Plan: From 30km per Week to the Finish Line
• Marathon Training Plans Fully Explained: The Advanced Path from Half to Full Marathon