BT attracted an extra 29,000 retail broadband subscribers between January and March 2017.
According to the company's latest trading statement, this took its overall retail broadband base to 9.3 million.
Demand for retail fibre broadband was particularly strong during this period, with more than half of its retail customers now on fibre.
BT also confirmed that Openreach achieved a record 520,000 fibre broadband net connections between January and March.
Service providers other than BT accounted for 59 per cent of these, which the company said demonstrates "sustained market-wide demand".
BT went on to note that it has now passed more than 26.5 million premises with its superfast fibre broadband network, while its ultrafast broadband deployment plans are also proceeding apace, with half a million premises now passed.
Furthermore, it pointed out that it is now offering to connect fibre-to-the-premises free of charge to developments consisting of at least 30 homes, as well as continuing pilots of its of G.fast technology.
BT added that its superfast broadband product performed strongly in Ofcom's most recent speed report, with the company found to have the smallest gap between peak time speeds and headline speeds of any broadband provider.