Strong demand for faster mobile internet has seen 2.9 million customers join the network since it was launched in October 2012, and the group expects to double that number before the end of this year.
However, first quarter turnover fell 3.6% on the year to £1.55 billion as it was weighed down by stricter rules on roaming charges and the fees that telecoms firms force on each other for connecting voice calls.
Despite these regulatory pressures, the group reported a 2.2% increase in mobile average revenue per user to £18.70, compared with last year. The rise is 5.1% when excluding regulatory cuts.
EE was the first mobile operator to launch 4G in the UK and its service now covers 200 towns and cities, or 72% of the population. The company also claims to be the only operator in the country to offer "double 4G speeds" at up to 60Mb/second in 20 cities, which it says is faster than most fibre broadband connections at home.
According to EE, mobile phone apps for US internet giants Google and Facebook now count for around a third of its 4G data traffic. Social media represented 21% of data use in March 2014, compared with 12% in April 2013.
EE is jointly owned by France's Orange and Germany's Deutsche Telekom. The parent companies surprised many in the City in January when they put plans to list the mobile operator on the stock exchange on hold, following a lengthy strategic review process.
Analysts had said the move could have valued EE at more than £10 billion, and there were also rumours that private equity firms could make a swoop for the group.