How Long Does The San Sebastian Festival Last?

San Sebastián, whose Basque name is Donostia and whose official name is Donostia / San Sebastián, is a small city on La Concha bay in Gipuzkoa, in the Basque Country of Spain, and for one week each August it doubles in noise, crowds and fireworks. The festival that draws the questions is Semana Grande, known in Basque as Aste Nagusia, and the answer to its length is fixed by rule rather than by announcement: it always occupies the week of 15 August, running Saturday to Saturday. In 2026 that meant 8 to 15 August. The tourism board publishes the rule, and each year's exact dates follow from it, so a traveller can work out the dates for any year without waiting for a programme.

How Long Does The San Sebastian Festival Last?

Semana Grande in San Sebastián lasts eight days, Saturday to Saturday, always in the week of 15 August. The 2026 edition ran from 8 to 15 August. The festival includes the International Fireworks Competition, and the closing Saturday night is the last night of fireworks. The rule is published by the tourism board, and the exact dates for a given year follow directly from it.

That "week of 15 August" rule does a lot of work. Because the 15th is the fixed point, the festival's start slides back and forth across the calendar: in 2026 the 15th fell on a Saturday, so the festival simply occupied the 8th to the 15th. In a year where the 15th falls midweek, the Saturday-to-Saturday window still wraps around it, so the festival always contains the Assumption public holiday of 15 August itself. Anyone booking flights for "the second week of August" without checking the calendar can arrive a few days early or late, so the practical advice is to find the Saturday on or before the 15th and count forward.

The fireworks competition is the spine of the week. Each night of the festival, a different pyrotechnic team fires a display over the bay, and the closing night decides the winner. The bay itself is the amphitheatre: the council's beach pages give La Concha as 1,350 metres of sand, and the promenade on both sides fills well before the first shell goes up. The festival programme also brings concerts, fairground rides on the Boulevard area and a general takeover of the Parte Vieja and the seafront, though the fireworks over the water are what many photographs of the week show.

Festival week is also the busiest week of the city's year in the hotel numbers. INE's hotel occupancy survey for the tourist point Donostia-San Sebastián recorded 245,769 hotel overnight stays in August 2025, the peak month of the year, against 115,910 in January. Those figures cover hotels only, not apartments or hostels, but the shape is clear: August holds a little over twice January's hotel stays, and the festival week sits at the top of that peak. Anyone who wants a room within walking distance of the bay during Semana Grande is booking into the most competitive week the city has.

Which Festival Do People Actually Mean In San Sebastian?

When people say "the San Sebastián festival" they almost always mean Semana Grande, the August week built around 15 August. But the city has several headline events with different lengths: the film festival runs about nine days in September, the La Concha regattas are rowed on the first two Sundays of September, and Jazzaldia and the Quincena Musical fill parts of the summer too.

The ambiguity is real because the city's calendar is crowded. The San Sebastián International Film Festival held its 74th edition from 18 to 26 September 2026, nine days of screenings centred on the Kursaal, whose own history page records the building's official inauguration on 23 August 1999. The La Concha regattas, the Bandera de La Concha, are rowed on the first two Sundays of September, with the women's race at 11:00 and the men's at 12:00, a championship first held in 1879 and with a women's flag since 2008. Jazzaldia, the jazz festival, ran its 61st edition in 2026, and the Quincena Musical ran its 87th edition from 2 to 30 August 2026, so the music season overlaps Semana Grande itself.

One festival must be separated out entirely, because it shares the name and nothing else. The San Sebastián Street Festival, the Fiestas de la Calle San Sebastián, takes place in San Juan, Puerto Rico, and has no connection to this Basque city. A search that mixes the two will return dates, music and geography that belong to another country. The same caution applies to the phrase "San Sebastián wine", which belongs to a winery in Florida; the local white of this city is txakoli, and there is more on the city's festivals, including the January and December events, in the San Sebastian festivals guide.

The table below sets the main events against each other, with the rule that fixes each one's place in the year. Where the pack gives an edition's dated example, it is included; where the rule alone is published, the table says so.

What Should You Plan Around Each Festival Day?

For Semana Grande, plan on eight days of fireworks, one each night, with the biggest crowds on the middle weekend and on the closing Saturday. For the film festival, plan on nine days of screenings concentrated around the Kursaal and the old town cinemas. For the regattas, plan on two separate Sundays, not a continuous event, with the racing finished by early afternoon.

The day-by-day shape of Semana Grande matters for anyone deciding how long to stay. The opening Saturday carries the launch, the middle days mix concerts and fairground atmosphere with ordinary city life, and the closing Saturday delivers the final fireworks and the prize. A visitor who stays only the first weekend gets the launch but misses the competition's verdict; a visitor who stays only the closing weekend gets the climax but pays peak-week prices for it. Since the festival always contains 15 August, a public holiday, expect shops and some services to run holiday hours on that day even as the festival runs at full volume. Other pages covering the same trip are gathered on San Sebastian Spain Guide.

The film festival works differently. Its nine days are a programme of premieres and screenings rather than a street party, and the energy concentrates in the evenings around the Kursaal and the Victoria Eugenia theatre district. The dates sit in the second half of September, when the seafront has already quietened: INE's hotel figures show September 2025 with 216,759 overnight stays against August's 245,769, a real step down but still the third-busiest month of the year. The beach lifeguards are on duty until 30 September, with hours cut to 13:30 to 19:30 from 16 September, so a film festival trip can still include the beach, just with an afternoon rather than a morning swim.

The regattas are the shortest festival of all in duration: two race days, each over by around midday. The traineras, the Basque rowing boats, race across La Concha bay, and the spectacle is watched from the promenade. Because the two Sundays are fixed by rule, a September visitor can often catch both the regattas and part of the film festival in one stay, which is one of the better-value combinations in the city's calendar.

Festival week also changes the pintxo bars. The Parte Vieja is the natural end point of any festival evening, and the bars fill after the fireworks clear. A guided food walk through that scene is one way to skip the guesswork of which bar is worth the crowd, and the pintxo crawl tradition is covered in the pintxos and food tours guide. For a fuller picture of the city beyond festival week, the things to do in San Sebastian page collects the year-round options.

When Is The Best Length Of Stay During Festival Season?

For Semana Grande, four to five nights is the practical sweet spot, long enough to cover a weekend and several fireworks nights without paying for the full week at peak rates. For the film festival, three to four nights covers the programme's core. For the regattas, a weekend stay that includes the first or second Sunday of September is enough, and it can be combined with the festival's opening days.

The reason is partly cost and partly saturation. Semana Grande's fireworks are nightly, so the marginal value of the fifth night is lower than the second, and the city's hotels price the whole week at peak. INE's figures show July and August 2025 together accounted for a heavy share of the year's hotel stays, and August is the peak, so festival-week rooms go early. The weather needs no exaggeration in either direction: AEMET's Igeldo station, 250 metres up on Monte Igeldo and so slightly cooler than the seafront, shows August averaging 19.5 C with a mean maximum of 22.5 C, but also 117 mm of rain over 10.5 rain days, more rain than June, July or September. Pack for warm evenings and at least one wet one.

September visitors get a different trade. The regatta Sundays and the film festival overlap the same fortnight, the sea is at its warmest after a summer of heat, and the crowds thin noticeably between August and September 2025. The trade-off is that the beach lifeguards finish on 30 September and the island boats' high season ends the same day, so late September is a city-and-culture trip rather than a beach trip.

How Do You Confirm The Dates For The Year You Travel?

You confirm Semana Grande's dates by applying the rule, the week of 15 August Saturday to Saturday, and then checking the organiser's programme for that year's concerts and fireworks schedule. For the film festival, regattas and Jazzaldia, the editions are annual but the exact dates are published each year by the organisers, so check the festival's own site before booking anything non-refundable.

This is the honest position for every event on the calendar. The rule for Semana Grande is stable and published; the detailed programme, including which pyrotechnic teams fire on which nights, is not. The film festival's length has been around nine days, but the printed dates belong to each edition. Jazzaldia's exact dates are not published as a standing rule at all. A traveller who books refundable accommodation and then locks in flights once the programme appears keeps every option open, and festival weeks are the one time of year when that discipline pays for itself.

For Semana Grande specifically, the booking window matters more than the dates. Because the rule makes the dates predictable years ahead, hotels price the week early and the bay-facing rooms go first. The San Sebastian film festival guide covers the September event's own logistics, and the Jazzaldia guide does the same for the jazz festival, including where its stages sit relative to the old town.

A food tour earns its place in a festival stay for a simple reason: the bars are at their fullest and least navigable precisely when the festival is at its best. A guided crawl with a local removes the trial and error.

Common Questions About The San Sebastian Festival

How long does the San Sebastian festival last?

Semana Grande, the festival most people mean, lasts eight days, Saturday to Saturday, always in the week of 15 August. The 2026 edition ran 8 to 15 August. The closing Saturday night carries the final fireworks of the International Fireworks Competition.

Is Semana Grande the same as Aste Nagusia?

Yes. Aste Nagusia is the Basque name for Semana Grande, and both refer to the same week-of-15-August festival in San Sebastián, in the Basque Country, Spain.

How long is the San Sebastian film festival?

The San Sebastián International Film Festival runs around nine days in the second half of September. Its 74th edition ran 18 to 26 September 2026, with screenings centred on the Kursaal.

When are the La Concha regattas?

The Bandera de La Concha is rowed on the first two Sundays of September, with the women's race at 11:00 and the men's at 12:00. The championship was first held in 1879, and the women's flag dates from 2008.

Is the San Sebastian Street Festival the same event?

No. The San Sebastián Street Festival, the Fiestas de la Calle San Sebastián, takes place in San Juan, Puerto Rico, and has no connection with the Basque city of Donostia / San Sebastián in Spain.

Does it rain during festival week?

It can. AEMET's Igeldo station shows August averaging 117 mm of rain over about 10.5 rain days, more than June, July or September, so pack for at least one wet evening even in festival week.

The short version: the August festival lasts a full week, Saturday to Saturday, every year, and the September events that share the city's name are shorter and worth planning around on their own dates.