The stats, which exclude traffic from tablets, show that on Sunday 14 July and on Saturday 20 July the majority of global hits to BBC News came from smartphones.
Traffic on the first day the site reached the milestone was largely driven by a story on the death of Glee actor Cory Monteith, according to Nathalie Malinarich, who is overseeing mobile editorially at BBC News.
On a typical day mobile phones (excluding tablets) contribute 42 per cent of the total traffic to BBC News, Malinarich told Journalism.co.uk.
The figures for mobile include people accessing the BBC News responsive website, those looking at the desktop site on a smartphone, and those using the BBC News apps.
Two other milestones
The royal baby story provided two other milestones for BBC News. Monday (22 July), the day of the birth, was a record day for mobile and tablet traffic, with the site being accessed from 9.2 million devices globally. The previous record was 7.8 million, which was following the Boston bombings.
Reports on the US election and Hurricane Sandy resulted in previous records for mobile for BBC News.
BBC News received record global traffic on the day of the royal birth, with 19.4 million unique browsers globally. It was the second biggest day in its history for UK traffic, just behind the response to its coverage of the 2011 riots."