Island of San Simón
Prison island in the inner Ría de Vigo, now a free-entry memorial and cultural site reached only by boat
Essential info
Visit details
Overview
The Island of San Simón sits at the head of the Ría de Vigo, off the parish of Cesantes in Redondela, and has served in turn as a medieval monastery, a maritime quarantine station and a Francoist prison camp. Nobody lives there now. The Xunta de Galicia runs it as a public cultural space, and in August 2026 the Spanish state declared it, together with its neighbour Santo Antón, a Lugar de Memoria Democrática.
What you visit is two islands, not one. San Simón and Santo Antón are joined by a short bridge and measure roughly 250 metres by 84 metres in total, with the islets of Cobreiras and Pena Blanca completing the archipelago. A channel separates them from the shore, and there is no way over other than by boat, even though the sand spit at Cesantes beach points straight at them.
The gardens are the surprise. Quarantine-era planting mixed shipped-in species with native ones, so Canary palms stand next to horse chestnuts, oaks, acacias, eucalyptus, Atlas cedars, Chinese privet and Japanese camellias.
The signature is the Paseo dos Buxos, a green vault of centuries-old box that runs down the central axis of the southern half of the island, from the chapel to the Boca da Ría viewpoint, and which is entered in Galicia’s catalogue of notable trees. There is also a small kitchen garden and nursery, planted to show crops that reached Galicia from elsewhere and changed its farmland: potatoes, maize, kiwi. During the thirty-odd years the island lay abandoned, wild growth took over and left it looking more overgrown than it ever had as a lazaretto, which is part of why the 1990s restoration involved as much clearing of invasive species as replanting.
Sculpture is scattered through the grounds and inside the buildings, with work by Francisco Leiro, Manolo Paz, Silverio Rivas, Jorge Barbi and others. Two pieces get most of the attention: Manuel Ferreiro Badía’s monument to the troubadours of the sea of Vigo, and a partly submerged tribute to Jules Verne and Twenty Thousand Leagues Under the Sea on the eastern shore, by Moncho Lastra and Sergio Portela.
Set expectations before you book. This is not a swimming island or a picnic island, and the rules say so plainly: bathing off the shore is banned and so is eating anywhere on the islands. You come for an hour or two of walking, reading plaques and looking at buildings that held people against their will. Vigo has beaches; San Simón has the other thing.
History
Monks, and the legend before them
Documented human presence starts in the 12th century, with a monastery founded by the Order of the Temple, though the site was probably inhabited long before and everything earlier belongs to legend. A small earlier monastery may have been caught by Almanzor’s troops in 997 and by Viking raiders soon after. The Templars stayed more than six decades, until the early 13th century, and remains of the two convents founded here are still visible.
Religious use ran on and off until the 18th century under several communities, including the Franciscan pascualinos, whose order was excommunicated in 1370 and left the island abandoned for close to a century before the Diocese of Tui ceded it to Isabella the Catholic. The same qualities that suited monks suited other people too. Soft, muddy bottoms in the ensenada made it a shelter and a hiding place for ships in trouble or being chased, which is a large part of why the island keeps turning up in stories about violence.
The island’s other medieval legacy is a poem. Meendinho set his single surviving cantiga de amigo at the hermitage of San Simón, a woman waiting for a lover who does not arrive, and it is treated as one of the high points of 13th-century Galician-Portuguese lyric. With Martín Codax and Johán de Cangas he makes up the trio of troubadours of the ría de Vigo, and the three of them share the sculpture in the grounds.
Drake, and the galleons at Rande
Francis Drake raided the Galician coast in 1589, a year after the Armada, and chronicles of the time say the last occupants of the convent were put to the sword. The raids eventually drove the monks off the island altogether, towards quieter ground near Redondela.
Before leaving, the English sacked San Simón, and the friar Jacobo de Castro recorded that they slashed the images of the saints and burned the church. The Battle of Rande was famous enough that London named a street after the victory, and the sunken gold has been hunted by expedition after expedition since, with Jules Verne only the best-known person to use it.
The lazaretto that built the port of Vigo
Everything you see standing today comes from 1838, when San Simón opened as a maritime lazaretto to relieve the one at Mahón, until then the only quarantine station in Spain. Ships bound for Galician and northern Spanish ports had to call here for sanitary inspection, and in its first twelve years the lazaretto processed more than 2,300 of them.
Within a few years the station was reclassified as a lazareto sucio, for the terminally ill with serious contagious disease, who were confined on Santo Antón while ships and passengers held on San Simón. The bridge between the two was flanked by two gates that only dying patients and the nuns nursing them were allowed to cross. Across 85 years the traffic of ships forced into the archipelago created shipping agencies and provisioning businesses on the mainland and helped turn Vigo into the leading port on Spain’s Atlantic coast. The park and the box walk date from this period too. The lazaretto closed in 1927.
Prison camp, 1936 to 1943
Plans to reuse the empty lazaretto as a seaplane base or an orphanage were overtaken by the coup of 18 July 1936. From October 1936 until 15 March 1943 the islands held political prisoners. More than 5,600 people passed through, though never more than about 2,000 at a time, and at least 517 deaths are documented, on top of executions and extrajudicial killings.
The state’s 2026 resolution divides the prison into three phases: detainees from Pontevedra province from October 1936; a peak from late summer 1937 to February 1939, when arrivals from Asturias pushed numbers past what the buildings could hold and a prison ship was moored to take the overflow; and a final phase from February 1939 to early 1943 in which elderly prisoners were sent here from across Spain and mortality rose sharply. The prison occupied San Simón; the military garrison and the cemetery were on Santo Antón. Sea, sentry boxes and patrols meant escapes were almost unknown.
Much of what is known comes from the prisoners themselves, through memoirs, letters, poems and drawings left by men including Evaristo Mosquera, Diego San José, Manuel Barros, Alfredo Bautista, Eduardo Pantaleón and Ernesto Carratalá, and from families who kept them when official records were damaged or destroyed.
Orphanage, abandonment, recognition
Afterwards the site housed members of Franco’s guard, until the launch A Monchita sank in 1950 killing 43 of them and the hostel closed for good; the cruceiro raised on the Cobreiras islet in 1958 remembers them. The Hogar Méndez Núñez, a home and training school for sailors’ orphans, ran from 1955 to 1963, after which the islands were left empty for about thirty years until a master plan in the 1990s began the rehabilitation.
Recognition came in two steps. San Simón and Santo Antón were listed as a Ben de Interese Cultural with the category of historic site on 29 July 1999. Then, by a resolution of 6 August 2026 published in the BOE on 21 August, the Secretaría de Estado de Memoria Democrática declared both islands in their entirety a Lugar de Memoria Democrática.
Visiting
Access works in two completely different ways, and knowing which one applies to you saves a lot of wasted email. The island’s own rules say every visit must be requested in advance in writing to illadesansimon.cultura@xunta.gal, that requests with a clear cultural or educational purpose will be authorised, and that purely private leisure visits generally will not. Groups going down that route also have to charter their own boat, carry public liability and accident insurance, and bring their own medical cover, because there is no medical staff on the island.
Two further rules catch groups out. The number of people allowed on the island per expedition is double the capacity of the boat carrying them, so a chartered 100-seat vessel means a maximum of 200 visitors in two trips, and never more than two trips in case the island has to be evacuated. The other is that the island supplies no guides at all. You may bring your own, and many groups do, but they are not allowed to use loudspeakers or any other amplification. Silence on the request also counts as a refusal: the Xunta undertakes to answer every application, and states that if no answer arrives the request is to be understood as denied.
For an individual traveller the practical route is a scheduled boat with a guided visit included. Piratas de Nabia runs it year-round, leaving Vigo’s Estación Marítima on Cánovas del Castillo at 16:30 and Cangas at 16:00, with both returns at 19:00, for about two and a half hours in total. Adults pay 20 euros, children aged 4 to 12 pay 10 euros, under-4s go free, and booking fees are extra.
The sailing itself is part of it. Boats from Vigo run up the inner ría and pass under the Rande bridge, the cable-stayed span opened in 1978, before entering the ensenada. Sailings can be moved or cancelled for weather or operational reasons, which in this ría is not a formality.
Once ashore, what is open to you is narrower than the island looks. Visitors may walk the gardens and the outdoor spaces of both islands, see whatever exhibitions are open, and go into the chapel of San Simón; where a cafeteria service is operating you can use it, along with the buildings that have public toilets. Every other building is closed to unauthorised people.
The chapel is worth the two minutes. Designed by Alejo Andrade Yáñez, it has a neoclassical ashlar front with a round-arched doorway, and the restoration stripped out a false vault to recover the original roof and added a porch on the east side so visitors have somewhere to shelter. Over on Santo Antón, the interpretation and documentation centre occupies the old hospitalillo of the dirty lazaretto, which later served as the soldiers’ quarters during the prison years and then as the clinic of the Hogar Méndez Núñez. It holds meeting rooms and a library of twenty reading places covering the ría, Galician history and art, medieval literature and historical memory.
Programming continues through the year and some of it is open to outsiders in one form or another: an August volunteer camp run by the Aventeira co-operative, which puts on staged guided visits for people from the surrounding area, the Con barqueira e remador international poetry translation workshop directed by Yolanda Castaño, and the San Simón Fiddle Camp for children run by the Asociación Cultural Galicia Fiddle.
Tips
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Book the scheduled boat rather than emailing the island, unless you are organising a school, university or cultural group. Individual leisure requests are, as a rule, not authorised, whereas the Vigo and Cangas sailings sell tickets to anyone and include a guide on the island.
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Note the departure time before planning your day. The boat leaves Vigo at 16:30 and Cangas at 16:00 and both get back at 19:00, so San Simón is an afternoon, not a morning; keep the rest of the day on the mainland.
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Eat before you board. Eating is not permitted anywhere on the islands, and bathing off them is banned, so a packed lunch and swimming things are both pointless.
The rest of the code of conduct is short and enforced. Smoking is banned inside every building and outdoors is limited to the landing quays and paved surfaces. Litter is treated seriously enough that the organising group can be billed for the clean-up. Pets are not allowed at all, guide dogs excepted. Children can come, under the supervision of an adult. There are security cameras across the islands, and the rules state that they do not record the images they capture.
- Take a windproof layer whatever the forecast says. The island is small, low and surrounded by water, and the only sheltered spot the restoration deliberately created is the porch added to the east front of the chapel.
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Bring binoculars if you have any interest in birds. The shallow ensenada uncovers sand and silt flats at low tide, and winter concentrates ducks and migrating waders alongside grey herons, gulls and cormorants.
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Walk the Paseo dos Buxos slowly and then double back through it. It runs the central axis of the southern half of the island between the chapel and the Boca da Ría viewpoint, and it is the one thing on San Simón that photographs better than it sounds on paper.
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For group bookings, contact the coordination service rather than the island. It is run by the Fundación Museo do Mar de Galicia at Avda. Atlántida 160, Alcabre, 36208 Vigo, on +34 986 247 750 extension 1, Monday to Friday 10:00 to 14:00.
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Allow lead time on any authorised group visit. Once approved you still have to give the island the boat’s arrival and departure times and its specifications, including length and draught, and the skipper has to follow the Consellería’s instructions for berthing and waiting.
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