Bookmaker Paddy Power said its online betting operations were going from "strength to strength" after it lifted profits by 15% last year.
The Dublin-based company has 209 shops in the UK but almost three-quarters of its 139.2 million euros in profits came online, having doubled its number of active customers to 1.6 million since 2010.
Much of the growth is due to betting through smartphones and tablet computers after mobile revenues increased by 185% last year.
Online profits grew 8% to 102.1 million euros in 2012 - or by 27% before investment in four new ventures - although UK retail profits also continued to grow strongly, up 46% to 15.3 million euros.
It pointed out that only 9% of the 333 billion euros global gambling market was currently online.
Paddy Power opened 44 new shops in the year but excluding the additional outlets betting volumes were still up 11% on a year earlier.
Last week, London's Newham Council rejected an application for a new shop because it said it flouted the 2005 Gambling Act on the grounds that it would make more money from gaming machines than from traditional betting.
Betting shops and casinos are allowed to offer machines which takes stakes of up to £100 and pay prizes of up to £500 and Paddy Power said it looked forward to the results of the Responsible Gambling Trust's major research project into machine gaming.
The company added that trading in January and February had been strong, helped by favourable sporting results. However it warned that the weakening pound against the euro could reduce operating profits by around 10 million euros this year.