In a statement, Dr Tim Kimber, senior partner at Park Surgery, announced that his surgery in St Floras Road, Littlehampton, and Westcourt Medical Centre in The Street, Rustington, will be joining forces this year in a merger.
He said it would see 'increased resilience in general practice locally, and even more seamless care, in a venture that will see the two practices sharing their strengths, and learning from each other'.
His statement said: "The two practices will combine forces to provide enhanced care in the community with a shared visiting team, and a strengthening of our ‘same-day-service’, operating from both sites.
"As far as most patients are concerned it will be ‘business as usual’, and the Partners of both practices are looking forward to providing even better services for their patients."
This comes as one of Littlehampton's other largest GP providers, Fitzalan Medical Group, was rated as 'inadequate' by the CQC despite making improvements.
There would be no obvious or immediate day-to-day changes, the statement said, and Dr Kimber assured patients they would still be able to see their usual team of doctors and nurses. Patients who usually attend the Westcourt Medical Centre building will 'generally continue to do so', and the same with patients of Park Surgery, the statement said.
The Care Quality Commission, the independent regulator for healthcare, rated both surgeries as 'good', the second highest rating, in reports published since October.
According to the CQC, Westcourt Medical Centre serves approximately 12,550 patients in Rustington, and Park Surgery has around 10,200 patients living in Littlehampton and Rustington.
Following the closure of Arun Medical Group's surgeries in the town in 2016, Westcourt took on 700 extra patients and Park took on 2,000, the CQC website said.