A 26-year-old woman from Swieqi is in critical condition after falling from a boat moored at Ta’ Xbiex.
The incident happened at around 12.30am.
The police said the woman fell into the sea and ended up between the boat she had been on and another vessel.
She was taken ashore by a man who was with her and other people who were nearby and offered assistance. She was then taken to Mater Dei hospital by ambulance.
An inquiry is being held.