Staycity will be opening 125 additional apartments as part of an expansion programme at its London Heathrow site next month.
The aparthotel operator will also open a guest lounge and café on the ground floor, as well as a breakfast area and terrace on the podium level.
Staycity will extend into its neighbouring property, taking the total number of apartments to 269.
Tom Walsh, chief executive at Staycity, said: "We have had a high level of interest in Heathrow since we opened. There is a strong demand from those travelling in and out of Heathrow as well as those taking the mainline rail out of London Paddington and people working with or visiting the many businesses in the area."
Earlier this month Staycity opened 170 new apartments in Birmingham's Newhall Square, the company's second site in the city.
The operator now has sites in eight European cities and has plans to expand from 1,000 apartments to 3,500 in the next two years.
It has a UK presence in Edinburgh, Manchester, Liverpool, Birmingham and London.