Nearly two million more Britons have come online during the last year, over half of which are over 50, according to new research.
The UK Online Measurement Company (UKOM) found that the net audience now stands at 38.8 million, up from 36.9 million at the same time last year.
The majority of internet newbies were made up of over-50s, with more men than women joining up.
Net services are increasingly targeting the older generation.
"The internet is getting older in more ways than one. Not only is the medium itself maturing but the audience is shifting towards older age groups," said Alex Burmaster, speaking on behalf of UKOM.
"There is a still a perception that the net is youth-centric but this is clearly not the reality," he added.
Over-50s account for 31% of the UK net audience. Men over 50 accounted for 38% of the 1.9 million new surfers.
Women over 50 accounted for 15%, women aged 21-34 for 14%, while girls aged 12-20 made up 12% of the total.
The older generation are attracted to a range of sites, including travel, genealogy, fashion, video and community sites, according to UKOM.
Health website RealAge and community site Saga are among the most popular with an over-50s market share of 89% and 78% respectively.