A 19-year-old man and a 17-year-old boy, both from Portsmouth, were arrested along with a 17-year-old boy from Fareham on suspicion of causing grievous bodily harm with intent in connection with an incident in Dormington Road on Tuesday.
A fight had broken out at 2.56pm, leaving three people injured and needing hospital treatment.
One of the victims, a 17-year-old boy, remains in hospital in a stable condition.
Two further victims, an 18 and 19-year-old man, have since been discharged.
The three males arrested in connection with the clash have been released on conditional police bail while police continue their enquiries to allow for a thorough investigation to take place.
Hampshire Constabulary said: ‘We would like to reassure the local community that we believe this to be an isolated incident at this time, with no wider risk to the public.
‘If anyone has any information or Ring Doorbell, mobile phone or Dash Cam footage of this incident, they should contact us on 101 quoting 44210480717.’