Strapped into a harness, hands clasped on a metal pole, I flew from Spain to Portugal at terrifying speeds along a 720-meter zipline that hung over the Rio Guadiana.
I had taken a boat from Alcoutim (on the Algarve side of the river) to Sanlúcar de Guadiana (in Andalusia). From there I was driven to a launch pad on a rocky peak with stunning views of both countries. did i scream As I raced to Portugal I tried to focus on these views: two dazzling white villages, the broad green river below, a Castle on the one hand, a Castillo on the other. It was all over in less than a minute, but thanks to the international time difference, I gained an hour.
The LimiteZero experience (the world’s only cross-border zip line) was just one of the highlights of a winding ride along the Rio Guadiana – the long river that originates in the Spanish province of Albacete and glides across the Portuguese border at Elvas in the Alentejo, heading south to the south Bay of Cadiz on the eastern edge of the Algarve.
My husband Dave and I traveled primarily on the Portuguese side of the river in a rented Fiat 500 and took six days for a three and a half hour trip. For much of the route, the river forms a natural border between Spain and Portugal; a number of castles and fortresses face each other from opposite river banks. Perhaps too many castles for one trip, but there are plenty of other things to see: salt marshes, walled cities and old river ports, lakes, river beaches, heavenly night skies, and the wild landscapes of the Alentejo’s Guadiana Valley National Park, where the river squeezes into craggy gorges and kestrels and golden eagles soar above the Pulo do Lobo (or Wolf’s Leap) waterfall.
A detour took us to the eerie ruins of the Sao Domingos pyrite mines, and later we continued to Elvas – a little-known frontier town with World Heritage status – only to see the remarkable Amoreira Aqueduct, seven kilometers long, which took more than 100 years to complete to build (from 1537).
At the start of our trip we rolled into Vila Real de Santo António, a pleasant border town on the Guadiana estuary with wide marina promenades and pine forest walks leading to the dunes of Praia Santo António – one of the east Algarve’s fabulously sandy and often deserted beaches.
Spaniards can take a ferry across from nearby Ayamonte – to shop (for towels, I’m told), eat fresh tuna, garlic prawns and cod stew at seafood cafes, or sit under orange trees in Praça Marquês de Pombal. The city’s marketplace is at the heart of a master plan drawn up by the Marquês de Pombal, who oversaw the rebuilding of Lisbon – and then Vila Real – after devastating earthquakes in the 18th century.
The city’s later prosperity rested on canned fish, an industry that all but died and looked unloved by the 1960s. Surplus canneries on the Spanish end of town still lie derelict, but the center’s ‘Pombaline’ architecture has been spruced up in recent years.
In the square, a delightful starting point is the Pousada de Vila Real de Santo António, open since July 2021, a collection of restored 18th-century buildings: a former kindergarten, the headquarters of the local communist party and part of the bank next door, with pools and Roof terrace with views of the Guadiana estuary (double rooms from €130).
Next stop was Castro Marim. Just a few minutes’ drive upstream, this old river port sits between the Guadiana International Bridge (a towering cable-stayed bridge visible for miles) and a swampy nature reserve with abundant birdlife (flamingos come and go). There’s a medieval castle with views across the marshes to Spain, but the town is best known for salt – a natural resource from wetlands that has been mined in the region for ages. Artisan salt panner Jorge Raiado offers tours and tastings at his family’s salmarim salt pans (Salt Pans) – white with sun-dried crystals harvested without machines or chemicals.
Our phones alternated erratically between Spanish and Portuguese time as we followed the river down a back road to Alcoutim. The home of the Zipline LimiteZero is set amidst orange, olive and almond groves and fig and apricot orchards on one of the most beautiful stretches of the Guadiana. The river beach Praia Fluvial do Pego Fundo is an oasis of cool, green water and soft, white sand imported from the coast. There is also a castle (first built by the Moors, rebuilt in the 14th century and rebuilt 100 years later) and an archaeological museum with Roman pottery and a collection of medieval stone board games. Sanlúcar, the city’s Spanish twin, is five minutes away by boat.
The site is popular with hikers, who come here to start (or finish) the Via Algarviana Trail, a 300km hiking trail that runs from Cape St Vincent to Alcoutim. The 165 km long Grande Rota do Guadiana (or GR15) from Vila Real to Mértola also passes through.
As we head north, the river swings away from the Spanish border into the Alentejo countryside, meeting Mértola on the edge of the national park. A maze of cobbled streets, cats and crumbling buildings, the little town cascades down from the craggy walls of yet another castle to the riverside quays and jetties. From pre-Roman times it served as a Gaudiana trading post, particularly important for the Moorish rulers who shipped grain and minerals downriver to Atlantic ports. Beneath the castle walls is the pretty 12th-century whitewashed church of Nossa Senhora da Anunciação, which was originally a mosque – one of the few relics of Portugal’s 500 years of Islamic rule. For a five-star view of Mertola from across the river, the budget Hotel Quinta do Vau offers double rooms from €40 per room.
Another hour’s drive took us north to Monsaraz, a charming town on a slate hilltop rising from the Alentejo plains Montada – a vast area of holm oak and cork oak forests, vineyards, farms and megaliths. Built of flinty metamorphic rock (wear sensible shoes), the pedestrianized walled streets and whitewashed houses offer dreamy views of Portugal’s largest artificial lake, formed by the Alqueva Dam.
Later we turned our gaze to the night sky. The Alqueva region is the first in the world to be recognized as a Starlight tourism destination thanks to clear skies, a sparse population and a collective effort to keep the lights down at night. Nestled in a forest on the edge of Lake Alqueva, the Montimerso Skyscape Country House features spacious suites and spacious terraces with Montada views and sun loungers for stargazing (from €200 B&B).
We were fortunate to choose a moonless, cloudless evening for a nighttime stargazing session at the ‘official’ Dark Sky observatory in a former elementary school in tiny Cumeada.
We stood in a courtyard and stared into space while our guide selected Pegasus, Taurus, Auriga and the Milky Way. Andromeda, just 2.5 million light-years away, is, he told us, the farthest we humans can see with the naked eye. We could see it here.
Then it’s back to earth, the way we came. I’d happily do it all again – maybe on the Spanish side of the river – although I’m in no rush to repeat the zipline experience.
The trip was provided by Visit Algarve. Visit visitalgarve.pt or visitportugal.com for more information