At 11h31 NSRI Simons Town crew were activated by the WC Government Health EMS following reports of a suspected drowning incident at Boulders Beach, Simons Town.A WC Government Health EMS ambulance and paramedic response team, NSRI Simons Town crew, CMR (Cape Medical Response), the SA Police Services and SA National Parks rangers responded.A 66 year old lady from Rondebosch, with a known heart condition, who had been swimming at Boulders Beach, was discovered lying face down in the water and was rescued from the water by an unidentified bystander. An off duty doctor, from Heideveld Day hospital, who happened to be on the beach at the time, were conducting Cardio Pulmonary Resuscitation (CPR) efforts on the lady.Paramedics assisted the doctor to continue with advanced life support CPR on the scene but after all efforts to resuscitate the lady were exhausted to no avail the doctor declared her deceased.Her husband was assisted on the scene by the emergency services.Her body was handed into the care of the Forensic Pathology Services and Police have opened an inquest docket. A post mortem will be carried out to determine the cause of death.It is unclear at this stage if the lady may have succumbed to a drowning accident or if she may have suffered cardiac arrest from a related medical condition while swimming.Our sincere condolences to her husband and loved ones.