Emergency services were called to Brighton Pier yesterday (Aug 1) following reports that an inflatable boat and a jetski had collided.
It happened just before 3.30pm. The woman on the jetski was taken to hospital with injuries that were not life-threatening.
Police said "the occupants of both craft are understood to be known to each other and the collision is currently being treated as accidental. No other information is available at this time."
Police, the coastguard rescue helicopter, ambulance and the RNLI all attended the scene.