And apps have now been downloaded more than 3m times.
The Beeb was keen on pushing live events to mobiles in 2013, demonstrated with its efforts for Glastonbury and Wimbledon.
Indeed, the latter worked wonders for BBC Sport, as 64 per cent of web traffic came from mobiles during the final.
Now, the division says mobiles fuelled 72 per cent of site visits on Boxing Day and 70 per cent on New Year's Day.
The devices brought in more than three million unique visitors on Boxing Day, reaching the three million milestone for the first time only to continue rising to hit a new record 3.1 million uniques on New Year's Day.
Tablets were key contributors, accounting for a record 1.3 million uniques on Boxing Day, surging to 1.5 million for the first time on New Year's Day.
The BBC Sport mobile app for mobiles has now been downloaded more than three million times across iOS and Android.
Chris Condron, head of product for BBC Sport, said: "These figures highlight just how essential handheld devices have become to our audiences. We’ve seen this trend grow throughout the year, culminating in record figures over the festive period when tablets and mobiles are a popular gift in many homes across the UK.
"We’ll continue to iterate and improve our digital services throughout a massive year of sport in 2014, making sure people get the best possible experience on any device they want, wherever they want."
Sister department BBC iPlayer has also reported a bumper mobile Christmas, claiming 2013 was year of the tablet.