The Times and Sunday Times now have more than 300,000 paid digital-only subscribers between them.
The titles, which both publish at thetimes.co.uk and on The Times mobile app, reached the milestone in June.
They now have 304,000 paid digital-only subscribers, up 19 per cent year-on-year, for a total of 539,000 paying subscribers (including print).
Digital subscribers pay £26 a month after an £8 two-month trial period.
The newsbrands also have some 5m “registered access” users who are able to read two free articles per week by signing up with an email account.
Chris Duncan, managing director of Times Newspapers, said the two titles “continue to show that people value quality journalism and are prepared to pay a premium for news they can trust”.
Owner News UK said 2019 had been its “most successful year” since launching a digital subscription model for the Times titles back in 2010.
It announced last year that digital subscribers had overtaken print for the first time for the Times and Sunday Times.
Digital subscriber cancellations at the Times and Sunday Times fell by half during a trial of a “digital butler” artificial intelligence software that tailors email newsletters to readers’ interests, it revealed in May.
In a recent speech to the Society of Editors, Times editor John Witherow said: “Ten years ago The Times pursued its own course…the paywall succeeded because we established a price for digital journalism.
“We recruited subscribers. We turned a profit. And we continued to invest in the highest quality journalism.
“This might seem obvious now but it is only with hindsight that we see that we were years ahead of our rivals.
“[The industry is] still an exciting place to be. It always will be. The task is to adapt to the new technology, to make it our friend, to put it at the service of our journalism.”