More consumers will use apps on their smartphone than a computer to do their banking by as early as next year, according to forecasts.
Last year, 22 million people managed their current account on their phone, industry analyst CACI said.
It has predicted that 35 million people - or 72% of the UK adult population - will bank via a phone app by 2023.
By then, customers would typically visit a branch only twice a year, it said.
CACI added that rural areas and smaller coastal towns would see the biggest increase in mobile users between now and 2023, owing in part to frustration over broadband access pushing customers towards mobile networks.
"With so much more functionality, mobile is rapidly becoming the digital channel of choice, and replacing traditional online banking for many customers," said report author Jamie Morawiec.
It would also mean banks might again review the location and number of branches.
Major UK banks have been closing hundreds of branches in recent years, with more plans announced recently.
Earlier this month, Royal Bank of Scotland announced it was to close 162 branches across England and Wales. Some 109 branches will close in late July and August 2018, while a further 53 branches will close in November 2018.
These branch closures follow existing plans to close 52 bank branches in Scotland that serve rural communities, and 197 NatWest branches.
Lloyds also announced recently that it was planning to close 49 branches.