From London, a lesson in the benefits of free Wi-Fi

The summer Olympics gave Britain not only a psychological lift, but a spate of free, public Wi-Fi networks as well. In preparations for the Games, the operators O2 U.K., Virgin Mobile, BT and The Cloud carved up public venues across the British capital, broadcasting open Wi-Fi networks in major public squares, airports and subways and on train platforms.

Free Wi-Fi service is becoming an important tool for operators in maintaining quality mobile service during a time of skyrocketing data traffic, congested mobile networks and, for travelers, costly roaming charges.

Public Wi-Fi networks have sprung up in many big cities. According to Informa, a research firm, the number of Wi-Fi hot spots worldwide will reach 5.8 million by the end of 2015, up from 800,000 in 2010. Eight of the world's 10 biggest mobile operators are using Wi-Fi to offload their cellular data traffic.

In New York City, free public Wi-Fi is available in 20 parks from AT&T. Google and Boingo, a maker of Wi-Fi equipment, sponsor free Wi-Fi at five New York subway stations. The city of New York is broadcasting free Wi-Fi from 20 pay phones.

In Paris, free Wi-Fi is available at some Metro stations, train stations and bus stops from a company called Gowex. In Hong Kong, the mobile operator PCCW runs 10,000 Wi-Fi access points, some free. In Tokyo, KDDI, another operator, has 120,000 hot spots.

In London, the rush to blanket public Britain with Wi-Fi attracted not only mobile operators like O2, owned by Telefonica of Spain, but the landline operator, BT, a virtual mobile operator, Virgin, and the satellite TV broadcaster BSkyB.

Virgin established Wi-Fi hot spots on 72 London Underground platforms during the Olympics and plans to cover 120 platforms, almost one in two stations, by the end of the year.

The service, which was used by a half million people during the Olympics, was initially free to all consumers. Starting this month, it has been available for a fee to other mobile users.

Virgin plans to lease its Wi-Fi underground network to competitors. Discussions with rivals are already under way, said Emma Hutchinson, a spokeswoman for Virgin Media in London.

The Cloud, a company that operates 11,000 public hot spots in Britain, most of them for free, offered free Wi-Fi on trains and in parts of greater London during the Games. Vince Russell, the managing director of The Cloud, which is owned by BskyB, the British satellite broadcaster, said next-generation cell networks cannot keep pace with rising mobile data traffic. "What you are seeing is a growth in hybrid networks, where you have cellular combined with Wi-Fi," Mr. Russell said.

O2 set up Wi-Fi networks in public squares across Westminster, Chelsea and Kensington, the most densely populated parts of central London. Consumers used networks at major crossroads like Trafalgar Square, Parliament Square, Leicester Square, Regent Street and Oxford Street. The networks were built by Ruckus Wireless, an equipment maker in Sunnyvale, California, that also supplied equipment to KDDI and PCCW in Asia.

O2 has leased the rights to operate its central London Wi-Fi networks for seven years, with the option to extend the lease for another three years.

Steven Glapa, the Ruckus Wireless director of field marketing, said operators were using Wi-Fi as another way to distinguish themselves from each other. "Competing for superior subscriber experience with Wi-Fi is a competitive advantage," Mr. Glapa said.

O2 said data traffic had risen threefold with its London Wi-Fi networks, which it is maintaining free to all consumers. Gavin Franks, the managing director of Wi-Fi for Telefonica U.K., said land-based Wi-Fi Internet access was integral to the industry's future. "This wasn't a gimmick for the Olympics," Mr. Franks said. "This is about how we see the long-term evolution of our network."

Philip Kendall, an analyst at Strategy Analytics in London, expects Wi-Fi rollouts to accelerate as operators compete for new turf and customers.

"They are a good part of the overall jigsaw puzzle of customer acquisition and retention," Mr. Kendall said. "This is a good cost-effective way of expanding the options and capacity for mobile data services."

Copyright 2012 The New York Times News Service