The Swim for Felix gala took place at the Mountbatten Centre in Portsmouth and attracted swimmers from eight local clubs to raise money for the Fit For Felix charity.
Entrance fees, merchandise and raffle ticket sales raised around £3,000.
The money raised will help pay for the daily care of Felix Barrow, 11, after he was involved in a life-changing car accident.
It will also help the Hampshire and Isle of Wight Air Ambulance, which took him to hospital after the incident on October 7.
Felix was hit outside his home in Swanmore and he was flown to Southampton General Hospital and placed in a medically-induced coma.
He had suffered a traumatic brain injury, which his parents were told would be potentially life-limiting.
Felix’s mother, Vanessa Barrow, 42 said: ‘Following the accident a lot of people wanted to do something. We are going to try and hold an event every month from now on.
‘Felix has done amazingly well. He used to swim twice a week, he is a very active young boy.’
The swimming clubs involved included Chapel Tri Stars, Fareham Nomads, Southampton Dolphins, Eastleigh Swimming Club, Hamble Aquatics and Portsmouth Northsea A and B teams.
Gary Cooper, head coach of Felix’s old club, Chapel Tri Stars, approached Portsmouth Northsea for help organising a fundraising event.
Helen Sullivan at Fareham Nomads and Hamble Aquatics chairman Jane Brown also helped organise it all.
The Mountbatten Centre halved the costs of pool hire as their contribution to the cause and Hinkley Antiques made the shield the teams were competing for.
Charlotte Budd said: ‘I heard about Felix because my son did a triathlon with him and I met his mum. Then I heard just one week later that Felix had this accident.
‘As a parent it really makes your stomach go, thinking if that had happened to your child.’