The move means millions of homes with new or re-contracting BT Broadband customers will have access to BT Sport for free for another season.
It comes ahead of satellite TV sports rival, BSkyB, expected to report tomorrow its first fall in TV subscribers in 15 years during the last quarter.
Both Berenberg and Credit Suisse analysts have forecast a fall between 5,000 and 15,000 traditional TV customers respectively for Sky's first three months of 2014.
BT has reported around five million homes now take BT Sport, just nine months after the channels went live for the first time last August. This makes BT Sport one of the fastest-growing TV services ever launched in the UK.
Around three million of those homes take the service directly from BT – either via satellite, BT TV or the BT Sport App alone – with the remainder taking the service via wholesale deals struck by BT.
In a statement today, BT Sport called its debut football season "strong", and noted viewers have also been able to enjoy exclusive live coverage of European rugby, Moto GP races, UFC, NBA basketball, women’s tennis and women’s football.
John Petter, chief executive of BT Consumer, said: "Fans have been the winners with BT Sport. Millions of homes have enjoyed the very best sporting action for free. We said we would shake up the market and we have done just that.
"The great news for fans is that BT Sport will remain free with BT Broadband for another season, during which we will broadcast live action from the new European rugby tournaments.
"There has never been a better time to switch to BT Broadband, so I would encourage sports fans to sign up."
BT also announced today that its set top box service BT TV has passed the one million milestone with the majority of those homes taking BT Sport.
BT TV customers can access more than 150 channels as well as a huge library of on-demand content, including premium movies and box sets, via their broadband.
BT Sport costs £12 a month in standard definition and £15 a month in high definition. Virgin Media customers have access to the BT Sport channels for the same price or as part of their package if they take XL broadband from Virgin.