Almost 381,000 accounts have been closed at Ulster Bank and KBC Bank Ireland since the start of the year, new data from the Central Bank shows, up from almost 293,000 at the end of August.
However, at the end of last month, 853,521 accounts remained opened at the two departing lenders.
That represents a reduction of 31% on the total at the start of the year, but still indicates that much work needs to be done before both banks can close their doors.
In total, 718,112 current and deposit accounts have been opened at AIB, Bank of Ireland and Permanent TSB since the beginning of this year.
The regulator said the rate of new account openings his picked up recently, with 95,410 opened.
But that rate is still lower than the volume of closures which has also accelerated over recent weeks, with 73,912 shut in the four weeks to the end of September.
Of the 495,032 current accounts that are still open, 407,124 are considered active and 296,578 were deemed by the banks to be the customer's "primary" account.
Last week, Ulster Bank said it would extend the deadline for those customers whose accounts were due to become non-operational last weekend by a further month.
The bank said the move was being taken to avoid unnecessary worry or complexity for customers in receipt of one-off and additional social welfare payments announced in the Budget last week.
First accounts that were due to become non-operational on 8 October, will now not become so until or after 4 November.
Meanwhile, the Small Firms Association has urged all small business customers of KBC and Ulster Bank to prioritise switching banking providers and ensure that all new bank accounts are set up correctly, so they can continue to make and receive payments.
"I understand the pressure business owners are currently facing from the energy affordability crisis and rising business costs," said Small Firms Association Chair Graham Byrne.
"However, now is the time to ensure that their banking services are not disrupted. This includes choosing a new provider, moving their balances and transactions, and closing their current and deposit accounts," Mr Byrne said.
He added that as Revenue's Pay and File Deadline approaches at the end of this month, businesses must also ensure their new account details are up to date with Revenue by using the Revenue Online Service at revenue.ie.
Mr Byrne said the urgency of the situation is underlined by the association's latest Cost of Doing Business report which found 22% of all businesses with fewer than 50 employees have borrowed in the last 12 months.
