The next generation of Internet giants gather this week in Portugal for four days of tech-fuelled networking, nights out and -- for the first time this year -- surfing of the offline variety.

Web Summit, which likes to promote itself as "the Davos for geeks" and provides a platform for startups to hook up with venture capitalists and hear about new trends from industry leaders such as Facebook, will see around 60,000 tech experts convene in Lisbon, where participants will look to catch a break either in or out of the water.

"Lisbon is kind of the surf capital of Europe, so not going surfing would be a very significant missed opportunity," said Web Summit CEO Paddy Cosgrave. 

Around 250 participants arrived in the Portuguese capital ahead of Tuesday's official start to enjoy some of Europe's best waves.

Mircea Baldean, founder and CEO of Canada-based startup MeetVibe, said he was looking forward to the networking opportunities at the event. 

"It's my first time in Lisbon, my first time surfing and my first time at Web Summit... as an entrepreneur you have to be ready to do new things every day."

But the event isn't all beach shorts and wipeouts: there's serious money up for grabs with some of the world's largest tech firms scouting for the next big app or technology in which to invest. 

Organisers claim that around a third of startups who display their products at the Web Summit find a donor within 12 months. 

"We've got 1,500 of the most active investors from around the world and a sample of 2,000 really high potential startups," said Cosgrave. 

Speakers at this year's event include former US President Al Gore, UN Secretary General Antonio Guterres and former olympian and campaigner Caitlyn Jenner -- as well as representatives from Internet giants such as Amazon and app-based behemoths Uber and Tinder.

- Work hard, play hard -

The stakes are high: organisers say one fifth of all venture capital invested in the last three years went to firms that participated in Web Summit -- accounting for tens of billions of euros. 

But they are also open about its out-of-hours approach to networking, and hope relationships forged in the bars and restaurants of Lisbon can go on to power the next waves of online innovation.

"The truth is a lot of the best relationships are built over dinner, over long walks in the city and other social activities. So we put a huge emphasis on what happens after 5 pm," said Cosgrave.

For Michael Memeteau, a founder of an energy startup who will be acting as an unofficial guide for one of the after-hours "pub crawls", it's the social aspect that makes Web Summit so popular.

"The thing is to keep some energy for the night, as the quality of exchanges is better," he said. "In fact I'm only going to go to three of the actual talks." 

Tommy Otzen, CEO of Danish start up Kubo Robot and winner of last year's Web Summit "Pitch" competition to find the best new firm, said his company received a one-million-euro investment off the back of the conference. 

"Our success at last year's Web Summit was what triggered that relationship, because we got a lot of media attention," he said.