Halifax and Starling gained the most current account customers between April and June 2021, according to the latest data from Pay UK.
Meanwhile, HSBC, Santander, and TSB experienced the biggest overall customer losses.
Here, Which? looks at the factors that may have encouraged people to switch to a new provider, and explains how easy it is to move to a new current account.
The most recent data from Pay UK shows the number of full account switches between 1 April and 30 June 2021.
The graph below shows how banks' and building societies' figures changed during this time - click on the tabs to see gains, losses and combined net gains of customers.
Halifax had the biggest net gain of customers during this time, at 16,684 - possibly due to the fact that it reintroduced its £100 switching bonus in April.
Other banks with positive net gains include Virgin Money, with 6,915, closely followed by Monzo (5,707), Lloyds Bank (3,875) and Nationwide (3,601). Monzo and Nationwide's relatively low net gains are surprising since these banks have been much more popular in the past.
In terms of attracting new customers, HSBC was top - 50,192 customers switched to the bank earlier this year. This may be down to the fact that First Direct (part of the HSBC Group) . However, this was outweighed by the fact that 66,756 people left to go elsewhere, giving it the largest net loss of -16,654.
Santander saw the second-largest net loss of -11,176, while TSB finished the period with a net loss of -9,491.
If you're in the market for a new current account, it's helpful to know which banks others have been switching to. But it's also worth knowing which providers are currently offering switching bonuses.
Available until midnight on 22 November, new First Direct customers can get £130 when they switch using the Current Account Switching Service (CASS), as long as you deposit at least £1,000 within three months of opening the account. You'll receive the bonus into your account within 28 days of the criteria being met.
If you make the switch to a Halifax Reward or Ultimate Reward account by 14 December, you could get £125. Note that the Reward account costs £3 a month unless you pay in at least £1,500 a month, and the Ultimate Reward account has a monthly fee of £17. Other caveats also apply.
New customers can get a £100 switching bonus for moving to a range of Nationwide current accounts, including popular FlexDirect, FlexAccount and FlexPlus accounts. Unusually, existing members can get an even bigger bonus of £125 if they switch and can do so by selecting 'Switch to Nationwide' in their online banking.
NatWest and RBS are both offering £100 for those that switch to their Select, Reward, Reward Silver, Reward Platinum or Reward Black accounts - note that some accounts come with extra fees and eligibility criteria.
You'll get a further £50 if you use the account for a year.
New and existing Santander customers who switch to the Santander 123, 123 Lite or Everyday accounts can get £130 as a switching bonus. The 123 and 123 Lite accounts offer 1-3% cashback on household bills, but they also come with a monthly fee so you'll need to weigh up whether it's worth it.
If you switch to a Virgin Money M Plus account as a new customer, you get the choice of receiving either a £150 Virgin Experience Day or a luxury case of 12 Virgin Wines worth £150.
If you apply via the Virgin Red website or app you can get 15,000 Virgin points for switching instead.
People often stick to the same current account provider for years, unless they encounter problems. But you could be missing out on extra perks like switching bonuses or linked savings accounts by shopping around for a new provider.
Of course, you shouldn't switch for the perks alone - before you take the leap, make sure the new bank account will suit your circumstances.
For instance, if you like to bank in-branch, make sure there's one nearby; if you prefer to use a banking app, make sure it offers all the services you'd need.
Our other guides also reveal the best accounts that offer extras, such as interest, cashback and packaged accounts:
Once you've found an account you'd like to switch to, you can apply to open it. Depending on the services it offers, you may be able to do this online, over the phone or in-branch.
If the provider is part of CASS, it should be opened and ready to use in seven working days.