Spain and Portugal share the Iberian Peninsula and a 1,234 km land border, and Spain is much the bigger partner: 506,030 km² against Portugal’s 92,225 km², about five and a half times the area. It also has more than four times the people, roughly 49.8 million in 2026 against about 11.4 million in Portugal (2025 estimate). It is somewhat richer per person too, with an IMF-estimated nominal GDP per capita of about $41,600 for 2026, compared with about $35,400 for Portugal. Madrid is Spain’s capital and Lisbon is Portugal’s. Spanish (Castilian) is Spain’s national language, with Catalan, Galician and Basque co-official in their regions, while Portugal’s official language is Portuguese. The two also share the euro, the Schengen area and one of the oldest land borders in the world.
Almost everything about the comparison makes more sense once you see how closely the two countries have been tied together, so this guide begins where they meet and only then sets out the differences.
La Raya: 1,234 km of Border Fixed in 1297
The Portugal–Spain frontier, known as La Raya in Spanish and A Raia in Portuguese, runs for 1,234 km, the longest continuous border inside the European Union. It was first defined by the Treaty of Alcañices in 1297, signed by King Denis of Portugal and Ferdinand IV of Castile, and has barely moved since. For long stretches it follows rivers: the Minho in the far north, 112 km of the Douro through narrow canyons, a short section of the Tagus, and the Guadiana in the south down to its mouth between Vila Real de Santo António and Ayamonte.
Couto Misto, Olivenza and a Zip Line Across the Guadiana
One sector of La Raya has never been marked. Olivenza (Olivença in Portuguese) was Portuguese from 1297 until 1801, when Spain took it during the War of the Oranges and kept it under the Treaty of Badajoz. The Congress of Vienna in 1815 asked Spain to hand it back, which never happened, so Portugal still does not recognise Spanish sovereignty there, and border stones numbered 802 to 899 along that part of the Guadiana were never installed. The dispute is mild in practice: Olivenza joined Portuguese towns such as Elvas and Campo Maior in a shared euroregion in 2008. Portugal and Spain both joined the Schengen area on 26 March 1995, and since then the busiest crossing, the bridges between Tui and Valença on the Minho, has carried about half of all road traffic between the two.
The frontier has its oddities. Until the Treaty of Lisbon of 1864, a tiny self-governing territory called Couto Misto survived on the Galician border, before being split between the two states. A wooden footbridge only 3.2 m long links the Portuguese village of Várzea Grande with El Marco in Spain, and a zip line from Sanlúcar de Guadiana in Spain to Alcoutim in Portugal is the only one in the world that crosses an international border. The open border was closed again during the COVID-19 pandemic in 2020 and 2021, when crossings were limited to goods, cross-border workers and exceptional cases for weeks at a time.
Tordesillas in 1494 and the Iberian Union of 1580–1640
The two kingdoms once divided the world between them. The Treaty of Tordesillas, signed on 7 June 1494, drew a meridian 370 leagues (about 2,100 km) west of the Cape Verde islands: lands to the east went to Portugal, those to the west to Castile. That line is why Brazil speaks Portuguese and most of the rest of Latin America speaks Spanish. The Treaty of Zaragoza in 1529 extended the division to the Pacific. Today Portuguese is spoken mainly in Brazil, Angola and Mozambique, and Spanish from Mexico to Argentina, so each language has far more speakers abroad than at home.
For sixty years the peninsula shared one king. After King Sebastian of Portugal died in battle in 1578 and his successor Henry died in 1580 without an heir, Philip II of Spain claimed the throne. The resulting Iberian Union was a personal union, not a merger: Portugal remained a separate kingdom with its own council and viceroys under Philip II, Philip III and Philip IV. It ended on 1 December 1640, when a revolt in Lisbon acclaimed John IV of the House of Braganza, and Spain accepted the outcome only in the Treaty of Lisbon of 1668, after the Restoration War. Portugal had in any case long looked to the sea and to England for allies: the Treaty of Windsor of 1386, still in force, is the oldest standing alliance in the world.
Salazar, Franco and Entry into Europe in 1986
In the 20th century the two countries followed parallel paths. Portugal lived under the authoritarian Estado Novo of António de Oliveira Salazar from 1933 until a military coup on 25 April 1974 launched the Carnation Revolution. Spain went through a civil war from 1936 to 1939 and then Francisco Franco’s dictatorship until his death in November 1975, followed by a new constitution in 1978. Both joined the European Economic Community together in 1986 and were in the first group of countries to adopt the euro in 1999. Their late democratisation shows in the numbers: Portugal recorded Europe’s highest illiteracy rate as recently as 1964.
Cooperation now runs through shared resources. The Albufeira Convention of 1998 governs how the two countries share their cross-border rivers, including the Douro, Tagus and Guadiana. The Tagus, at 1,007 km the longest river in Iberia, rises in the Montes Universales between Cuenca and Teruel in eastern Spain and reaches the Atlantic at Lisbon, so Portugal depends on water released upstream in Spain. The two countries bid jointly for the 2018 World Cup without success, and will co-host the 2030 FIFA World Cup with Morocco.
Madrid’s Scale Against Lisbon’s Atlantic Edge
Size shapes almost every comparison. Spain has an Atlantic and a Mediterranean coast, the Balearic and Canary Islands, and the cities of Ceuta and Melilla in North Africa. Portugal faces only the Atlantic, but its autonomous regions of the Azores and Madeira extend its territory far into the ocean. Madrid sits near the centre of the peninsula; Lisbon sits at the mouth of the Tagus, which makes it the westernmost capital of mainland Europe.
The income gap between the two is smaller than the size gap. Spain’s total economy is estimated at about $2.09 trillion for 2026, the 14th largest in the world, against about $381 billion for Portugal. Spain’s lead per person is about 17 per cent at market exchange rates and narrows to about 12 per cent once prices are taken into account. Both economies lean heavily on visitors: Spain received 94 million international tourists in 2024, second only to France, and Portugal nearly 30 million in 2025, a very high figure for a country of 11 million. Both populations are ageing, with Spain’s median age at 46.8 years. On the UN Human Development Index for 2023, Spain scores 0.918 (28th) and Portugal 0.890 (40th).
Castilian, Catalan, Galician and Portuguese
Portugal is one of Europe’s most linguistically uniform states, and Portuguese is spoken almost everywhere. The recognised regional languages are small: Mirandese in Terra de Miranda near the northeastern border, and Barranquenho in Barrancos on the Spanish frontier. Spain is multilingual by design. The 1978 constitution makes Castilian Spanish official nationwide and lets other languages become co-official in their autonomous communities. About 99 per cent of residents use Spanish as a first or second language, while Catalan or Valencian is the first language of 10.5 per cent, Galician of 3.8 per cent and Basque of 1.4 per cent.
Galicia, in Spain’s northwest corner just across the Minho, is where the two worlds overlap. Portuguese and Galician grew from the same medieval Galician-Portuguese tongue, first spoken between the Atlantic and the Douro in what is now Galicia and northern Portugal. The County of Portugal, founded in 868 on the frontier between the Limia and the Douro, took its name from Portus Cale, today’s Porto. A Galician speaker in Tui and a Portuguese speaker in Valença can usually follow each other. Spanish and Portuguese in general are closely related Romance languages, and much written Portuguese can be read by Spanish speakers. The political tensions of regional nationalism also belong to Spain alone: Catalonia held an independence referendum in October 2017, after which its parliament voted to declare independence unilaterally, and the Basque armed group ETA dissolved in May 2018.
Teide, Mulhacén and the Meseta Central
Mainland Spain is dominated by high plateaus, above all the Meseta Central around Madrid, and by mountain chains: the Pyrenees along the French border, the Cantabrian Mountains, the Sistema Central and the Sierra Nevada, where Mulhacén rises to 3,479 m, the highest point on the Iberian Peninsula. Spain’s summit overall is Mount Teide on Tenerife in the Canary Islands, a volcano of 3,715 m. The Ebro and the Guadalquivir are entirely Spanish rivers, running to the Mediterranean and the Atlantic respectively.
Serra da Estrela, Mount Pico and the Tagus Divide
Portugal is lower and more Atlantic than Spain. The Tagus divides it neatly: about 95 per cent of the land above 400 m lies north of the river, in the granite hills of Minho, Trás-os-Montes and the Beiras, while south of it the Alentejo and Algarve are mostly rolling plains, with 62 per cent of the land below 200 m. Mainland Portugal’s highest point is Torre in the Serra da Estrela at 1,993 m, but the country’s true summit is Mount Pico, a 2,351 m volcano in the Azores. Portugal’s climate is milder and wetter on the northern coast, while inland Spain has hotter summers and colder winters. For more on how the two fit on a map, see whether Spain is bigger than Portugal, and for the capitals themselves, our guides to Madrid and Lisbon, capital of Portugal.