Hounslow Council this week ended months of uncertainty by naming the firms set to manage its leisure services from July 1.
John Laing Integrated Services and Fusion Lifestyle will run facilities across the borough, from libraries to swimming pools, after CIP's contract runs out at the end of this month.
The council chose the companies in April but delayed the announcement until Monday for 'legal and commercial reasons'.
John Laing, which is better known for building hospitals and roads, will be responsible for parks, libraries and art centres. Fusion, which already runs gyms in several other boroughs, will be in charge of leisure centres and sports development.
Both companies have been chosen as the council's 'preferred bidders' and will only become its official contractors if conditions are met. The new contracts will last for between 10 and 15 years.
Cllr Adrian Lee, lead member for leisure and culture, said the firms had been chosen because of their proven track record of 'excellence and innovation'.