Few destinations have witnessed a boom in tourism over the last few years quite like Portugal. According to the United Nations World Tourism Organisation (UNWTO), the country welcomed 6.8m overseas arrivals in 2010. By 2016 that figure had grown to 18.2m – an increase of 168 per cent. Globally, only Japan has seen a sharper rise in visitors this decade.

The UNWTO’s latest report does not have an exact figure for 2017, but last week Portugal’s economics minister gleefully reported that tourism revenue increased by 17 per cent, year-on-year, in 2017, and a further 14 per cent so far in 2018. “Portugal is living in a good moment of tourism,” said Manuel Caldeira Cabral.

But at what cost to the experience of both visitors and locals?

Unchecked tourism is good for the economy – but it causes problems. Rapid growth means strained infrastructure and overcrowding in big cities and at major attractions. During recent months we have seen rising tension between locals and visitors in destinations including Barcelona, Venice, Amsterdam, Dubrovnik, Madrid, Kyoto and Mallorca, and “overtourism” has become something of a buzzword.

Caldeira insists Portugal is coping with the surge in visitors. Speaking at a World Travel & Tourism Council Leaders’ Forum in Lisbon, he highlighted efforts to encourage travel outside of the peak summer season, the promotion of trips to lesser-known destinations, as well as the construction of new hotels.

But his optimism isn’t shared by those living in Portugal. “Overtourism is definitely an issue in Portugal, mostly in Lisbon and Porto,” said Trish Lorenz, a journalist and resident of the capital. “The surge has happened very quickly and infrastructure isn’t keeping up. There are huge queues for tickets at railway stations, standing room only on public transport, and issues around noise and litter mean locals are increasingly fed up.” She added that landlords were increasingly favouring lucrative short-term lets, offered through websites like Airbnb, leading to the eviction of many residents from the city centre.

Lorenz’s comments paint a similar picture to the one seen in Venice, a city locals claim has been “Disneyfied” and lost to tourists.

“In both Lisbon and Porto the central downtown areas have become more or less only for tourists,” she said. “Lisbon’s Baixa district, for example, which covers an area of 1.5 square kilometres, now has more than 70 hotels, while tourist-oriented restaurants, souvenir shops and big international brands have displaced local businesses.”

A tour bus in Lisbon Credit: GETTY

Anti-tourist sentiment is growing, Lorenz claims, particularly among young residents who have been priced out of the housing market. She also highlighted the closure by local authorities of a popular Lisbon bar following complaints from a newly-opened five-star hotel. “When I first moved here five years ago people would come up and chat to me and were very welcoming,” she said. “Today, assuming I’m a tourist as I do not look Portuguese, they push past me in queues.”

Mary Lussiana, Telegraph Travel’s Portugal expert, agrees with the assessment. “Lisbon is suffering the most, with the narrow cobbled streets so crowded with tourists, particularly in areas such as Chiado, that it is hard to walk around,” she explained. “Locals talk of an invasion and tell stories of long-time tenants being kicked out of their houses to make room for Airbnbs. The community, a hugely important part of Portuguese life, is under threat. Worst of all are the huge cruise ships, which pull into Lisbon and disgorge thousands of passengers who contribute nothing to the city as their food and lodging is on board. The situation is definitely not sustainable.”

A cruise ship departing the Portuguese capital Credit: GETTY

So what can tourists do to help? Going somewhere other than Lisbon and Porto would be a good start. Thanks to the emergence of budget airlines like Ryanair and EasyJet, we are living in the age of the European city break. Research by the ONS last year found that Britons are increasingly favouring regular weekend escapes over longer itineraries. But when thousands are doing likewise it causes problems. So ignore social media and the so-called travel “bucket list” – and pick somewhere less obvious. Below, Lorenz and Lussiana nominate their favourite unsung Portuguese highlights.

Five underrated Portuguese destinations you should visit instead

Coimbra

“With Lisbon and Porto bearing the brunt of overtourism there are other interesting Portuguese cities to explore,” says Lorenz. “Coimbra, halfway between Lisbon and Porto, is a former capital and has a pretty and well preserved medieval old town and a university known for its historic buildings, including a beautiful baroque library. A large student population means the bars and restaurants are lively and there’s a good live music scene too.

Historic Coimbra Credit: GETTY

“Other options include Aveiro, known as the Venice of Portugal, thanks to its network of canals and colourful boats, and the medieval cities of Guimarães and Braga in the far north, each with a raft of castles and churches, along with a great culinary tradition.”

Alentejo

“This region which stretches across Portugal above the Algarve remains a place of rural tranquillity,” says Lussiana. “Pick any of the white-washed, medieval hilltop villages and you will find yourself only surrounded by Portuguese. But for a healthy dose of culture stay for a few days at the old convent in Vila Viçosa, now a pousada complete with original frescoes. Once occupied by Romans and then the Moors, it is a gem of a town dominated by the impressive ducal palace built in 1502 from the famous local marble.”

No tourists here: Rural Alentejo Credit: GETTY

Lorenz adds: “Rural Alentejo is one of the country’s least explored regions. Rolling countryside is dotted with olive and cork plantations, small farms, vineyards and sleepy villages of white-washed cottages. Restaurants serve simple, hearty home-made fare and excellent wine at low prices. Towns such as Montemor, Evora and Vila Vicosa have a rich history and the region has a small selection of boutique hotels such as São Lourenço do Barrocal, Monte Velho and L’And if you need a little bit of luxury.”

Olhão

“The little town of Olhão has managed to survive the overdevelopment that much of the Algarve has suffered due to a lack of hotels,” says Lussiana. “Yes, daytrippers come to see the famous domed fish market, the region’s best, but when they have left there is the perfect sunset to watch undisturbed from atop one of the flat roofs of this white-washed Moorish town which faces the Ria Formosa. The narrow streets remain a warren of tiled, coloured facades, unchanged for centuries and storks still nest in the bell towers of the churches.”

Explore the narrow streets of Olhão Credit: GETTY

Comporta

Lorenz writes: “If the Algarve’s beaches are too busy for your taste, you’ll find plenty of unpopulated sandy stretches further north. Comporta, 70 miles south of Lisbon, is surrounded by rice fields and pine forests and has more than 35 miles of deserted sandy beaches. If you’ve heard tales of Ibiza in the 1970s, Comporta has much the same vibe today – bohemian, laid-back and quietly upmarket.

“About the same distance north of Lisbon, Peniche is a fishing village that is only now beginning to welcome international visitors. Rustic and simple, it offers access to a number of pristine beaches and plenty of small restaurants offering fresh seafood.”

Empty sands in ComportaG Credit: GETTY

Serra da Estrela

“The highest mountain range in continental Portugal is famous for both their mountain dogs, which are large, territorial and highly intelligent, and their sheep’s milk cheese,” explains Lussiana. “Sparsely inhabited, this is a region far removed from the tourist areas of Portugal. In their place are birds of all variety from short-toed eagle, European honey buzzard, Montagu’s harrier, black stork, pygmy owl, blue rock thrush, and ortolan.”