The 2026 San Sebastián Rural Kutxa Half Marathon takes place on Sunday 4 October at 9:30am from Donostia’s Boulevard. It is a 21.097km city-road race, officially certified by the RFEA, with both start and finish in the same place. That makes it a sensible place to chase a personal best, but not a race to improvise: a flat course can punish an over-ambitious opening just as efficiently as a hilly one.
This final-week guide turns the organiser’s information into useful decisions: when to collect your bib, how to use pens and pacers, what to carry, how to pace the 21K and what not to introduce on Sunday. The cut-off is 2 hours 30 minutes and this edition’s bibs are sold out.
Key details for Donostia’s 21K
- Date and start time: Sunday 4 October 2026, 9:30am.
- Start and finish: San Sebastián Boulevard.
- Distance: 21.097km, a city-road course officially certified by the RFEA.
- Time limit: 2:30, with a cut-off pacer.
- Aid stations: water at 5K, 10K, 15K and 20K; HSN product and bars are also planned for 15K.
- Live timing points: 5K, 10K and 20K, as well as the finish.
Certification means the course has been measured through the official procedure and that 21.097km is the reference distance. It does not mean every GPS watch will show exactly that. Wide lines through turns, overtaking and ordinary GNSS error often add distance. On race day, trust elapsed time and the kilometre boards first; instantaneous watch pace is useful information, not the authority on your race.
Bib collection: the simplest problem to avoid
Bibs can be collected at the Boulevard’s Welcome Zone on Saturday 3 October, from 2:00pm to 7:00pm. Runners who chose an alternative collection shop can collect from 30 September through 3 October during that shop’s opening hours. The organiser is explicit: there is no Sunday bib collection. For Boulevard collection, bring the registration confirmation containing your QR code.
Handle it calmly on Saturday, then make one race-morning bag: bib already attached, pins or belt, familiar shoes, tested socks, before-and-after layers and the nutrition you have already practised. The day before a half marathon is not the time to swap insoles, debut a shirt or decide that an unfamiliar gel will probably work.
Pens and pacers: choose honestly
There will be three start areas. The organiser assigns access by bib colour and asks runners to respect their designated pen. That may sound minor, yet lining up near your real pace reduces early braking and helps prevent the opening kilometres becoming a series of sudden evasive moves.
The announced pace groups target 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 2:00 and 2:30. Treat them as reference points, not contracts. If your training suggests 1:45 but you arrive with poor sleep, a niggle or an uneven final week, starting two or three minutes more cautiously can produce a much better half marathon than trying to survive the theoretical pace.
- 1:30: 4:16/km average.
- 1:40: 4:44/km average.
- 1:45: 4:59/km average.
- 1:50: 5:13/km average.
- 2:00: 5:41/km average.
- 2:30: 7:07/km average.
Those figures are arithmetic over 21.097km, not a prescription. If your watch rounds pace or records more than the official distance, do not try to solve it with abrupt changes. Check your splits every 5km and look for sustainable effort: demanding but controlled breathing, a stride that is still intact and the ability to make a sensible choice at 10K.
A pacing plan that protects the second half
A flat profile invites runners to set one number and simply repeat it. In practice, a half marathon is decided by the cost of holding that number after the early excitement disappears. For many runners, a sound approach is to run the opening 3km just below target intensity, settle from 4K to 15K, and only then decide whether there is genuine room to press.
- 0-3K: find space and do not trade a few seconds for a heart rate you cannot bring back.
- 4-10K: establish steady pace without chasing every GPS fluctuation.
- 11-15K: use official splits to check sustainability; this is better adjustment territory than attack territory.
- 16-20K: if your form still looks like your normal running, build progressively; if you are at the limit, protect pace and take aid stations calmly.
- Final 1.097K: run by feel and position, not by a changing screen number.
A half marathon does not require a perfect negative split. It also does not reward trying to prove fitness you have not confirmed. If the second half ends up two or three seconds per kilometre slower because it is not your day, staying composed will usually beat chasing the original goal until you unravel.
Aid stations: decide before you are thirsty or empty
Water is planned at 5K, 10K, 15K and 20K. A runner close to 90 minutes may not need in-race energy; for longer finishing times, warm conditions, lower tolerance for load or runners accustomed to carbohydrates, following an established plan can help. The useful rule is simple: do not make the official station your first test of a drink, a bar or caffeine.
If you plan to drink, anticipate the table, move over gradually and ease pace for a few seconds so you can swallow safely. You do not need to finish the cup. If you use a familiar gel, take it with water if that is what works for you, and do not wait until you are depleted to decide. Over 21K, fueling should support your training, not attempt to rescue an over-fast start.
Final week: fewer new ideas, more clarity
Five days out, fitness is not won; fatigue can still be added. Keep easy runs genuinely easy, reduce normal volume and retain only a brief touch of pace if it is already part of your routine. Sleep, familiar food and settled logistics matter more than one late workout.
The day before, a short walk or very easy jog may be useful for some runners and unnecessary for others. What matters is that it does not create soreness or anxiety. Eat what you tolerate, prepare the breakfast you know and decide in advance how you will reach the Boulevard. The organiser recommends arriving with time to spare and respecting the assigned pen.
What to follow from home
The race can be followed live through the official website, with timing points at 5K, 10K and 20K. For friends and family, picking one of those points is more useful than trying to move around repeatedly without a plan. For runners, those splits will help explain the race afterwards: not only how fast it was, but where the effort actually changed.
Sources and editorial approach
Race date, start time, certification, cut-off, bib collection, pens, pacers, aid stations and live tracking come from the organiser’s runner information and the 2026 regulations. The event’s place in the national calendar was cross-checked with the RFEA. This is a practical pre-race guide: it does not anticipate results or treat changeable weather conditions as settled fact.