The coffee shop chain, owned by the Whitbread Group, also highlighted its equity stores, which delivered like-for-like sales (LFLs) of 7.1% for the 24 weeks to 16 August 2012.
Costa said it benefited from “relatively poor weather” during the second quarter of 2012, which some of its food-to-go rivals, such as high street bakery firm Greggs, pinpointed as a factor for a drop in sales and footfall.
Andy Harrison, chief executive of Whitbread, said: “Whitbread has continued to deliver good sales growth with total sales up 14.8% in our second quarter. Our brands have outperformed in a tough economic climate, with LFLs growth of 4.2% and we have continued our network expansion at Costa and Premier Inn.
“Costa had yet another strong quarter, with LFLs up 5.7% and total sales up 25.3%, as we continue to grow at pace in both the UK and selected overseas markets. The economic challenges and variable trading month by month continue. We remain on track to deliver our ambitious growth programme, with our strong brands winning market share.”
The coffee shop brand said it had opened 50 net new UK stores during the quarter, with 39 retail outlets and 11 under it Costa Enterprises business.
Costa Enterprises, which includes the company’s Express units, found in locations such as motorway service stations, delivered system sales of £101.8m, an increase of 33%, with a total of 1,974 Costa Express units.
Costa increased its overall system sales by 22.9% to £432m, with its total franchise system sales up 18.9% to £175.6m. International system sales also grew by 20.7% to £95.8m.
The company has said it plans to open 350 net new stores and 1,000 Costa Express units in the full year.
Costa has also been growing its international footprint, with the first store in Singapore opened during the quarter, and a further 12 sites operating in the period, taking its total number of outlets in Asia to 199.