A 26-year-old Italian woman was seriously injured on Thursday evening after jumping into the sea at Peter's Pool, limits of Marsaxlokk.
The incident happened at 7pm, although police said they were only called to the scene at around 8.15pm.
Civil Protection Department members lifted the woman to safety and she was subsequently rushed to Mater Dei hospital by ambulance.
She is the third person to require medical intervention following dives into the sea at Peter's Pool this summer. In late June, a Swedish 21-year-old man and 18-year-old Swiss hurt themselves in the same manner in the space of just two days.
Correction: Police subsequently said that the incident happened on Thursday evening, not yesterday as originally stated.