Turnover in the same period was £1,037m, down 5% from £1,089m.
Profit before tax rose 2% to £184.9m for the Cardiff-based firm which also has offices in Swansea and Newport.
Henry Engelhardt, chief executive officer, said their expectations for the UK business in 2014 "remain unchanged".
The chief executive also said there are some signs that premiums in the UK are no longer falling but he added "we have yet to see firm evidence of an inflection point and a return to premium growth".
He said Admiral's premium rates have been "pretty flat" over the first half of the year, although, as a result of the reductions in 2013, total premiums were down around 9% compared with the first half of 2013.
Admiral's other brands include Elephant, Diamond and Bell. It now insures more than 130,000 additional customers in the UK than it did this time last year.
Mr Engelhardt added: "Outside the UK, our international insurance operations continue to grow and make progress.
"Our European price comparison businesses had a profitable first half of the year and we're encouraged by the very early indicators from comparenow.com in the US."
Car insurer Admiral has announced customers rose by 9% to 3.94 million in the first half of the year, although there was a 5% drop in turnover.