Your First Marathon: The Complete Beginner's Guide to Preparing (and Finishing)

TL;DR — For your first marathon, plan 16-20 weeks of training, 3-5 runs per week, a long run that builds up to 30-32 km, a 3-week taper, and 30-60 g of carbs per hour on race day. Never run the full 42.195 km in training. Pick a race that motivates you, not the "most prestigious" one. And forget the time goal: for a first marathon, finishing is the goal.

You're going for your first marathon. Good news: it's one of the rare things in life where finishing is itself a victory — regardless of the time, the marathon changes you. Bad news: there's a lot of bad advice on the internet, and half of first-time marathoners "blow up" between km 30 and km 35 due to under-preparation.

This BPMoov guide gathers what the best coaches and training plans (Boston Athletic Association, Marathon Handbook, data from hundreds of thousands of finishers) recommend to prepare a first marathon properly — with a practical focus: pick your race, train without injury, finish on your feet.

How long does it take to prepare for a first marathon?

16 to 20 weeks. That's the standard you'll find from most serious coaches and federations. Specifically:

• 16 weeks = the minimum window to build your aerobic base, absorb long runs, weather a 1-2 week setback (illness, work, life), and taper properly before race day.
• 20 weeks = the norm for a true beginner or someone returning from injury. More buffer, less temptation to push too fast.
• 24-28 weeks = needed if you're starting from zero (never run before or very little). That's "couch-to-marathon" — possible, but ambitious.

The absolute minimum to avoid injury: you need to be able to run 30-40 minutes continuously without stopping when you start your marathon plan. If not, do 8-12 weeks of easy base running first.

Picking your first marathon: the decision that changes everything

This is the first real decision, and the most important one. Don't get fixated on prestige (Paris, Berlin, NYC...). For a first marathon, look for:

1. A flat to moderately rolling course. Not a vertical trail. Flat asphalt is your friend.
2. A race in a temperate region, ideally spring or fall (April-May or September-October). You don't want to discover heatstroke on your first marathon.
3. A motivating context: friends running the same race, a city you want to discover, a race that's iconic to you. Your head matters as much as your legs.
4. Simple logistics: ideally within 4 hours of home to limit travel stress.

A few French classics good for a first marathon: La Rochelle, Bordeaux, Nice-Cannes, Toulouse, Mont-Saint-Michel… For the details (course, date, profile, registration windows), see our complete guide to the 10 best marathons to run in France in 2026.

Practically: open the BPMoov app, filter by distance "marathon" and region, save 2-3 candidates to your favorites to compare dates, registration openings and prices. → Download the app.

The standard training plan: 16 weeks, 4 pillars

The standard structure for a beginner marathon plan:

Total weekly volume starts around 25-30 km and progressively builds to 55-65 km at peak (weeks 12-13), then drops during the taper.

4 golden rules:

1. Never increase by more than 10% per week. The "10% rule" prevents 80% of overuse injuries.
2. 3 weeks build, 1 week recovery. Mandatory cycle to avoid burnout.
3. 80/20: 80% of volume at easy pace (able to talk), 20% at sustained pace. Way too many beginners run all their easy days too fast.
4. One day of cross-training (cycling, swimming, yoga, strength) builds cardio without impact.

The long run: pillar number 1

If you take one thing from this guide: the long run is non-negotiable.

• Start at 12-15 km in week 1
• Build to 30-32 km at peak (weeks 13-14)
• You will NEVER run 42.195 km in training. The jump from 32 km to the marathon happens thanks to adrenaline, taper and race-day fueling.
• Very easy pace — able to talk, even hum
• Time, not distance: your longest run should last 2:30 to 3:00 max. Beyond that, the recovery cost outweighs the benefit.

The long run is also where you test all your race-day logistics: shoes, clothing, gels, electrolytes, hydration belt. No new gear on race day — that's marathon golden rule #1.

Nutrition: what nobody tells you

Your body stores about 300 g of glycogen in muscles and liver — roughly 1.5 to 2 hours of running. Beyond that, without external fuel, you bonk (the famous "wall"). To finish 42 km, you need a nutrition strategy.

The 3 days before the race (carb loading):

• Bump carbs to 65-70% of total calories
• Pasta, rice, white bread, fruit — not the moment to test new foods
• Cut fiber to limit GI surprises on race day

Race morning:

• Breakfast 3 hours before the start
• 200-400 calories, mostly carbs
• Example: oatmeal + banana + honey + black coffee
• Drink 500 ml of water in the 2 hours before

During the race:

• 30 to 60 g of carbs per hour (gels, isotonic drinks)
• First gel around km 8-10, then every 30-40 minutes
• Drink at every aid station (every 5 km on most marathons)
• Never skip an aid station even if you feel fine

Pacing: the catastrophe to avoid at all costs

80% of "first marathons gone wrong" go out too fast. Start-line adrenaline tricks you into thinking you can hold a pace you can't. Result: explosion between km 30 and km 35, then 7 km of run-walk agony to the finish.

Pacing strategy that works for a first marathon:

1. Calculate your target pace: double your recent half-marathon time + 10-20 minutes
2. Run the first 10 km at 10-15 sec/km SLOWER than your target pace
3. Settle into target pace between km 10 and km 30
4. If you feel good, lift slightly after km 30 — that's the negative split

Analysis of 100,000+ Boston finishers shows runners who go out more than 3% too fast miss their goal by at least 8 minutes. Conservative pacing is statistically the most profitable.

Tapering: never skip this step

The 3 weeks before the race = taper. You progressively cut volume while keeping a little short intensity. Standard scheme:

• Week -3: 80% of peak volume
• Week -2: 60% of peak volume
• Week -1: 35-40% of peak volume + total rest the last 2 days

It will feel counterintuitive: you'll feel like you're "losing fitness". You're not — tapering lets your body repair micro-injuries, top off glycogen, and restore your immune system. The studies are clear: a good taper buys you 2-3% of performance on race day.

Race week: checklist

Your D-7 → D-0 checklist:

• D-7 to D-3: progressive carb load, hydration +20%, sleep priority (8h+)
• D-2: bib pickup, easy on your feet (no long sightseeing walks)
• D-1: LIGHT pasta party in the evening, early to bed, no alcohol
• D-0: wake 3 hours before, tested breakfast, 10-15 min warmup, conservative start

BPMoov tip: save your race to favorites in the app to receive registration reminders, logistics briefings, and timely confirmations. No more stress missing a step. → Download the app.

Classic mistakes to avoid

• ❌ Testing new shoes, gels or clothing on race day
• ❌ Skipping the taper (or confusing it with "doing nothing" — you still run a little)
• ❌ Eating heavy the night before (3-cheese lasagna = bad idea)
• ❌ Going out too fast because "it feels easy"
• ❌ Stopping at aid stations without drinking (the silent dehydration error)
• ❌ Picking a marathon "for prestige" without checking the profile
• ❌ Comparing your time to other first-time marathoners (every body is different)

Ready to pick your race and start training? BPMoov brings together race registrations for road and trail marathons across France and Europe — free, iOS and Android, 2,000+ races indexed. → Download the app.

FAQ — First Marathon

How long does it take to train for a first marathon?

The standard window is 16 to 20 weeks. 16 weeks is the safe minimum for someone who can already run 30-40 minutes continuously. 20 weeks is recommended for true beginners or returning from injury. Starting from zero, plan 24-28 weeks.

What is the maximum distance to run in training before a marathon?

Between 30 and 32 km, or 2:30 to 3:00 max on a single long run. You will NEVER run the full 42.195 km in training — the jump happens thanks to taper, adrenaline and race-day fueling.

How many carbs per hour during a marathon?

30 to 60 g per hour for a beginner, meaning 1-2 energy gels + isotonic drink at aid stations. First gel around km 8-10, then every 30-40 minutes. Elite marathoners target 60-90 g/h, but that's too much for a first marathon.

What's the best first marathon in France?

It depends on your region and target date. A few classics for beginners: La Rochelle, Bordeaux, Nice-Cannes, Toulouse. See our complete guide to the 10 best marathons to run in France in 2026.

How many times a week should you train for a first marathon?

3 to 5 runs per week for a beginner. Standard structure: easy run x2, pace session x1, long run x1, plus ideally one cross-training day. Beyond 5 runs/week, injury risk rises without extra benefit for a first marathon.

What time should you target for a first marathon?

Forget the time. For a first marathon, goal #1 is to finish on your feet without injury. If you want an estimate, take your half-marathon time, double it, add 15-20 minutes. The real performance is holding a steady pace over 42 km — not going out fast.