More than 250,000 people ditched their current bank for a new account in the past first three months of the year.
The latest figures from the Current Account Switch Service show that digital bank Monzo was the biggest winner when it comes to sheer numbers, with 20,843 new current account customers.
John Crossley, head of money at comparethemarket.com, said: "Digital banks, which accounted for over 30,000 switches in March – over one quarter of total switches.
"Monzo, for the first time ever, also had the highest gains of any bank. Once seen as the banks for trendy Millennials and Generation Z, the challenger banks are fast becoming mainstream.”
But while Monzo saw eight people join for every person who left, it was blown out of the water in terms of ratios by ethical provider Triodos - which had almost 13 people switch to it for every person who left.
Gareth Griffiths, head of retail banking at Triodos Bank UK, said: “People are now looking for tangible changes they can make to contribute to a better way of living, as well as lowering their impact on the environment.
"Switching banks is one of the most powerful environmental changes you can make as an individual."
Other big winners were Starling (with seven joiners for every leaver) and Ulster Bank (2.4 people new customers per leaver).
Nationwide, Lloyds, NatWest and HSBC - whose figures include people switching to First Direct - also saw more people join than leave.
At the other end of the scale, it was Bank of Ireland that saw the worst figures - where more than 50 people switched away from it for every new joiner.
There were also net losses of customers for AIB Group, Tesco Bank, Co-operative Bank, Halifax, Danske, Clydesdale, TSB, RBS, Santander, Bank of Scotland and Barclays.
Overall, 6.6 million bank accounts have now been switched since the launch of the Current Account Switch Service in 2013 - a million of them in the past year alone.
The service guarantees all your direct debits and payments are moved across to your new account within seven days.
Andrew Hagger from MoneyComms said: "Switching activity was strong in February (96,122 switches) and March (113,037 switches) - the latter the third highest monthly total on record.
"This increase in people moving accounts will have been fuelled by the banks announcing massive hikes their overdraft charges, so the Q1 figures for 2020 will make interesting reading and show which banks have suffered the most for charging rates of up to 49.9% EAR ( in the case of Lloyds Bank) for agreed overdrafts."
