When is the 2027 Biarritz Half Marathon?

On Sunday 25 April 2027, starting at 8:30 am at the Aguilera sports ground. The marathon starts at 7 am on the same day.

Is the Biarritz Half hard?

It is hilly: 305 m of climbing announced over 21.1 km, between central Biarritz, Bidart and the ocean front. It is not a course for a flat-road personal best.

How do you enter the Biarritz Half?

Online on the official website, open for 2027. The price rises after the first 1,000 bibs, all races combined. An FFA licence or PPS health pass is required.

Semi-Marathon International de Biarritz: how many weeks of preparation?

For an athlete at intermediate level, Endu builds a 13-week preparation. If your race is closer, the plan compresses phases while keeping the taper; if it's further away, it lengthens the preparation, and when the gap is large the preparation starts right away, gently and at your current volume, before building up.

How many sessions per week?

This example has 4 sessions per week. You choose 3 to 7 training days and the exact days (e.g. Tue, Thu, Sat, Sun): the plan sticks to them.

I'm a beginner, is this plan for me?

The plan adapts to your declared level (beginner to semi-pro): starting volume, progression and intensity change. Endu also offers a "Discovery" mode without a race to build a base first.

Can I follow sessions on my watch?

Yes, on Garmin and COROS. On Garmin, the Endu app (Connect IQ Store) shows today’s session and starts it as a guided workout. On COROS, link your account from your profile: your running, trail and cycling sessions land in the watch calendar. Other brands are not supported yet.

How much does it cost?

14-day free trial, then €7.99/month with no commitment or €59.88/year (€4.99/month). Unlimited objectives and sports.

Semi-Marathon International de Biarritz 2027: date, course and training plan

21.1 km · 305 m D+Biarritz2027 edition: 25 April 2027

The Biarritz Half Marathon is part of the Matmut Marathon de Biarritz – Pays Basque, created in 2022, which drew 18,000 runners across all races in 2026. The half starts at the Aguilera sports ground, loops out to Bidart and comes back along the ocean front, with 305 m of climbing: the organisers openly describe the course as hilly. Next edition on Sunday 25 April 2027, starting at 8:30 am.

Your plan for Semi-Marathon International de Biarritz

25 weeks to go: your plan starts this week, set to your level and free days, then adapts to your feedback after each session.

Your goal time?

14-day trial, cancel anytime.

Semi-Marathon International de Biarritz at a glance

Date: 2027 edition: 25 April 2027
Formats: Semi-marathonPlan below — 21.1 km, 305 m of climbing, 8:30 am start from the Aguilera sports ground, on Sunday 25 April 2027. Four aid stations. Over-18s only.
Marathon — 42.195 km, 7 am start; also run as a three-person relay.
14 km la Boucle des plages — 14 km around Biarritz including the seafront, 11:45 am start.
10 km chrono — 10 km, 7:15 am start.
Registration: Registration for 2027 is open on the official website, online until 6 am on race day while bibs remain; the price goes up after the first 1,000 bibs (all races combined). An FFA licence (Athlé Compétition, Entreprise or Running) or a PPS health pass is required. Bib transfers go through the website, until 19 April 2027; cancellation cover is available as an option. According to the provisional programme, bib pick-up is at the Halle Iraty on Saturday 24 April, from 9 am to 5 pm.
Official website: marathonbiarritz.com/fr

The 2027 course

Start from the Aguilera sports ground. The half is almost entirely within Biarritz, with a short incursion into Bidart: the historic town centre, stretches along the ocean front and past the foot of the Biarritz lighthouse, then back to Biarritz along the coast.

What the race asks of your training

305 m of climbing on a half

305 m of climbing is a lot for a road half: the organisers say the Basque Country has to be earned. Put hills into your build-up, both as sessions (6 to 10 climbs of 1 to 2 minutes) and in your long runs, rather than relying only on reps on the flat.

A pace that varies

Between the climbs, the descents and the seafront, the pace per kilometre cannot be even. Think in terms of effort rather than time: run your hilly long runs at a steady feel, and learn to relax on the descents without braking.

Aid stations without cups

The half has four aid stations, with food and drink, but no paper or plastic cups are provided: bring your own cup, soft flask or vest. Do your long runs with the same container, and test your drink and gels on them.

The plan below prepares the Semi-marathon format, for an athlete at intermediate level with 4 days available per week, with race day on 25 April 2027. Aiming for another format? Enter its distance when you create your plan, which will be calibrated on your level, your available days and your feedback after every session.

weeks: 13
sessions: 52
sessions / week: 4
peak week: 4.9 h

Plan structure

Periodised in phases: build the base, move to race-specific work, then taper before the race.

General preparation
Weeks 1–2 · 2 wk
Base
Weeks 3–5 · 3 wk
Build
Weeks 6–7 · 2 wk
Specific
Weeks 8–10 · 3 wk
Taper
Weeks 11–12 · 2 wk
Race week
Weeks 13–13 · 1 wk

Volume progression

Week by week: lighter recovery weeks are built in to absorb the load.

Wk	Phase	Hours	km
1	General preparation	2.8 h	28
2	General preparation	3 h	30
3	Baserecovery	2.4 h	23
4	Base	3.3 h	33
5	Base	3.6 h	36
6	Build	3.8 h	40
7	Buildrecovery	3 h	30
8	Specific	4.2 h	42
9	Specific	4.5 h	45
10	Specific	4.9 h	49
11	Taper	3.5 h	34
12	Taper	2.7 h	26
13	Race week	2.3 h	22

Sample week — week 8 (Specific)

Real sessions from the plan with their targets. Each session is detailed step by step, and can be sent to a Garmin or COROS watch.

MondayEasy
51 min easy
51 min · 8.2 km
TuesdayVery hard
6 × 800 m at MAS
2 min jog recovery
57 min · 10.8 km
WednesdayEasy
51 min easy
51 min · 8.2 km
SundayModerate
Long run 1 h 31
last 11 min at marathon pace
1 h 31 · 15.1 km

Example generated for a intermediate-level profile (MAS 15 km/h, 4 days available per week). Your plan will depend on your level, availability and feedback.

This plan’s check-up

Pass

A 13-week build (recommended minimum: 8); a longest run never more than 10% above the previous month’s; volume rising at most 11% from one week to the next; 90% of the time at easy effort; the longest session 3 weeks before the race; a taper cutting volume by 53% in race week.

2 worth knowing · 16 checks passed

Remarks

Strength training — No strength session.
Fueling — Long sessions (up to 105 min in this plan) are where race fueling is rehearsed.

The 16 checks passed, in detail

Length of the build — 13 weeks: enough for this race (recommended minimum: 8).
Sessions per week — 4 sessions a week: the minimum for this race is met.
Volume progression — Running volume rises at most 11% from one week to the next (a signal appears beyond 20%).
Long run increase — Each week, the longest run is at most 10% longer than the longest of the previous month (benchmark: 10%).
Lighter weeks — A lighter week comes back regularly (weeks 3, 7, 11).
Weight of the long run — The long run keeps a reasonable share of the week.
Intensity distribution — About 90% of the time at easy effort: the most common distribution among trained endurance athletes.
Demanding sessions — No more than 2 demanding session(s) a week: suited to the level.
Hard days back to back — Demanding sessions are separated by easy days.
Rest days — At least one rest day a week.
Easy run pace — Easy runs are truly easy (slower than 5:43/km).
Race-specific work — 7 race-specific sessions in the last block.
Timing of the longest session — The longest session falls 3 weeks before the race: the right time.
Taper — Volume drops 53% in race week.
Intensity during the taper — Short race-pace efforts remain in the last two weeks.
Frequency during the taper — The number of sessions stays close to usual (100%).

Endu runs its own plans through the plan check open to everyone: same public rules, same thresholds, same sources. The rules and their sources, and a check of your own plan.

Why this plan works

Science-based periodisation

Base → build → specific → taper, with a recovery week every 3 to 4 weeks. Load goes up, but never two hard weeks in a row without a breather.

Paces, not vague feelings

Every session has target zones (pace, HR) computed from your MAS or a reference performance. A MAS test is built into the plan if you don't know yours.

A plan that listens

After each session you rate how it felt (RPE). Too hard? The plan eases what follows. Skipped a session? It reschedules or absorbs it.

On your watch

On Garmin with the Endu app, on COROS by direct sync: the guided workout shows up on your wrist, step by step.

Reviews

What our users say.

4.8/5

“I used to spend more time looking for a plan than following one. Now I have my sessions, I know what to do and I stick to it. Really glad I tried it.”
Thomas · Running
“Training for my first half marathon and honestly, I’m getting into it! I even look at my next sessions ahead of time, when before I was mostly looking for an excuse not to go out 😂”
Camille · Running
“Simple to follow and really handy with the watch. I start my session and off I go.”
Julien · Running
“I took Endu to prepare a trail race with friends. I really like having my week already organised: it motivates me and I enjoy my runs more.”
Émilie · Trail
“What I like is no longer asking myself a thousand questions before going for a run. I follow the plan and I enjoy training.”
Nicolas · Trail
“With work and the kids, I thought I’d struggle to follow a plan. In the end, having a structure helps me a lot. Running has found a real place in my week again, and it feels good!”
Julie · Trail
“A good find to prepare my swimrun! It’s nice to find a plan for this sport. I’ve recommended it to my teammate.”
Antoine · Swimrun
“I run more regularly and, above all, with more desire. For that alone, I’m delighted.”
Laura · Swimrun
“For triathlon, having all three sports in the same schedule really makes my life easier. I spend less time organising my training and I still enjoy following it just as much.”
Maxime · Triathlon
“At first I just wanted to try it. Now checking the next day’s session has become my little evening ritual 😊”
Sarah · Triathlon

Your plan, not a template athlete's

This plan is generated for an athlete at intermediate level with 4 days available per week. Yours will be calibrated on your MAS, your available days and your feedback after every session. 3 minutes. 14-day trial, cancel anytime.

Create my plan for Semi-Marathon International de Biarritz