The firm will start work on site for Arun District Council next year.
Willmott Dixon has delivered more than £100m of leisure facilities in the past six month including new centres in Tewkesbury, Dartford, Scarborough, St Albans, Oldham, Hebburn, High Wycombe and Romford.
Littlehampton Leisure Centre will feature an eight-lane, 25 metre swimming pool, learner pool, gym, dance and cycling studios, sports hall and café.
Councillor Paul Dendle, Arun District Council’s Cabinet Member for Leisure and Amenities, said: “We are delighted to announce Willmott Dixon as the successful company. They have a proven track record in delivering similar projects and we are excited about seeing this major project get underway.”
Arun District Council procured Willmott Dixon through the Southern Construction Framework.
Roger Forsdyke, managing director of Willmott Dixon construction in Cobham, said: “We’ll be working closely with Arun District Council to provide the local community with much needed new facilities.”