How Long Does It Take to Train for a Half Marathon? 8, 10 and 12-Week Options

The half marathon is one of the most popular goals among runners. At 21.1 km, it is demanding enough to require proper preparation while remaining accessible to runners who build a consistent routine.

One question comes up more than any other: how long does it take to train for a half marathon?

For most runners preparing for the distance for the first time, the most sensible answer is at least 12 weeks. World Athletics recommends allowing a minimum of 12 weeks and gradually increasing the distance covered. It also offers a beginner programme based on three weekly sessions, focused on consistency, confidence and endurance.

However, the right training period depends primarily on your starting point. Someone who already runs regularly and can comfortably complete 10 km will need a different plan from someone who has only recently started running.

Can you train for a half marathon in eight weeks?

It is possible, but it is not generally the best option for someone starting from zero.

An eight-week plan may be appropriate if you already:

• Run three or four times each week;
• Can comfortably complete between 10 and 12 km;
• Have maintained a consistent training routine;
• Are not returning from an injury;
• Want to finish the race rather than chase an ambitious time.

In this situation, the eight weeks can be used to gradually extend your long run, practise hydration and nutrition and become comfortable running for longer periods.

If you are still alternating short intervals of running and walking or struggle to train consistently, choosing a later event will give you a more realistic preparation period.

What about ten weeks?

Ten weeks can be enough for someone with previous running experience who has not yet completed 21.1 km.

Ideally, you should already be able to run between 8 and 10 km at a controlled effort. From there, you can gradually extend your long run while keeping most of your other sessions shorter and easier.

Avoid turning every session into a test. The purpose of training is not to prove every weekend that you can already complete a half marathon. It is to develop enough endurance to arrive at the starting line healthy and prepared.

Twelve weeks: a balanced option for beginners

For many runners, 12 weeks provide a good balance between progression and recovery.

This gives you time to:

• Build a routine without increasing your training too quickly;
• Develop endurance through progressively longer runs;
• Work on pace without making every session intense;
• Test hydration, gels and your pre-race breakfast;
• Include easier weeks when necessary;
• Manage minor interruptions without losing the entire plan.

Training plans do not need to look identical for everyone. World Athletics provides options for different experience levels and incorporates activities such as strength training, yoga and swimming alongside running.

When should you allow 14 to 16 weeks?

A longer preparation period is advisable when:

• You are new to running;
• You have recently returned after a break;
• You cannot yet comfortably complete 8 to 10 km;
• You can only train three times per week;
• You tend to experience pain when increasing your mileage;
• You prefer a more gradual approach.

Having more weeks does not necessarily mean doing more training. It means having enough time to progress without pressure and repeat a week when your body needs longer to adapt.

What should a half marathon plan include?

A beginner plan can be built around three main weekly sessions.

One easy run

This should be completed at a comfortable pace at which you could still hold a conversation. Easy sessions allow you to build mileage without creating excessive fatigue.

One focused session

This may include short changes of pace, a progressive run, hills or a few controlled minutes near your intended race pace.

It does not need to be extremely intense. Its purpose is to introduce variety and gradually improve your running efficiency.

One long run

The long run is the main reference point of half marathon preparation. Its duration gradually increases, helping both your body and mind adapt to longer periods of exercise.

It is also the best opportunity to test the shoes, clothing, hydration and nutrition you intend to use on race day.

Strength or cross-training can also be included, provided that rest and recovery remain part of the programme.

How do you know you are ready to begin?

You do not need to be fast, but some consistency is important.

You are probably ready to start a half marathon plan when:

• You can train at least three times each week;
• You can run 8 to 10 km without finishing completely exhausted;
• You recover normally between sessions;
• You are not dealing with persistent pain;
• You can keep easy runs genuinely easy.

If you are not there yet, the half marathon is not out of reach. You may simply benefit from spending a few additional weeks building your base first.

Which half marathon should you choose in Portugal?

For runners beginning their preparation at the end of July 2026, the calendar offers several events with different amounts of training time available.

Around six to eight weeks: for runners with an established base

17th Half Marathon of the Municipality of Castro Marim “Flor de Sal”

12 September 2026 | Altura, Castro Marim

This night race consists of four laps of a road circuit, starting at 20:00 with a two-and-a-half-hour cut-off. The programme also includes a 10.5 km minimarathon, providing an alternative if you reach race week without feeling ready for the full 21.1 km.

Half Marathon da Benedita

13 September 2026 | Benedita, Alcobaça

The event includes a half marathon, 10 km race, 5 km walk and Kids Run. The half marathon has a three-hour time limit, and registrations made through its RaceFinder page are managed directly by RaceFinder.

Half Marathon Loures–Odivelas–Loures

20 September 2026 | Loures and Odivelas

The race connects the two municipalities on an internationally certified course. The programme also includes a 10 km race, a 5 km option and children’s races, allowing participants to adjust their goal if their preparation does not progress as expected. The half marathon cut-off is three hours.

These events are more suitable for runners who already train consistently. Those still developing their base should consider a race in October or November.

Around nine to eleven weeks: for runners with 10K experience

Ameal Half Marathon 2026

27 September 2026 | Coimbra

The certified half marathon course has approximately 66 metres of total elevation gain. The event also offers a 10.3 km race and a 10 km walk. Its relatively flat profile may appeal to runners looking for a controlled first experience or an opportunity to target a faster time.

Half Marathon de Ovar

4 October 2026 | Ovar

This established event includes a certified half marathon, a competitive 10 km race, a walk and a children’s race. Its range of distances makes it suitable for friends or families arriving with different objectives.

Hyundai Lisbon Half Marathon

11 October 2026 | Lisbon

The race begins on the Vasco da Gama Bridge and finishes at Praça do Comércio. It has a maximum capacity of 11,000 runners, different starting corrals and a three-hour cut-off. It is a strong option for anyone looking for a large-scale race and an iconic urban course.

Twelve weeks or more: stronger options for a first training cycle

Half Marathon Leiria

18 October 2026 | Leiria

With a half marathon, 10 km race, walk and Kids Race, the event combines competition with family participation. The 21 km race has a three-hour cut-off, aid stations along the route and registrations managed directly by RaceFinder.

Cascais Oeiras Lisboa 2026

8 November 2026 | Cascais, Oeiras and Lisbon

The point-to-point coastal course starts at Casino Estoril and finishes at Praça do Império in Lisbon. In addition to the half marathon, the programme includes a 10 km race and a relay, giving runners other ways to participate without completing the full distance individually.

The best plan begins with a realistic race date

A half marathon does not begin at the starting line. It begins when you select an event that suits your experience, availability and current fitness.

For runners with an established routine, eight or ten weeks may be enough to turn an existing base into race-specific preparation. For a first half marathon, 12 weeks remains a more balanced target. Those who are new to running or returning after a break will normally benefit from choosing an event 14 to 16 weeks away.

The most important factor is not following an exact number of weeks. It is training consistently, respecting recovery and arriving on race day healthy.

Explore upcoming half marathons in Portugal on RaceFinder and choose the next goal for your calendar.