At 15h13, Wednesday, 10 February, NSRI Simon's Town duty crew were activated following reports of a drowning in progress at Kalk Bay harbour.The sea rescue craft Spirit of Surfski II was prepared to be launched and NSRI rescue swimmers, CMR (Cape Medical Response) paramedics, CoCT (City of Cape Town) Fire and Rescue Services, CoCT Lifesaving lifeguards, CoCT Law Enforcement and the SA Police Services responded.While responding to the scene it was confirmed from eye-witnesses that a male teenager was missing under water.An NSRI Simon's Town rescue swimmer happened to be at the harbour at the time and he immediately kitted up into his wet suit and approached the scene at the same time that a CMR paramedic and NSRI Simonstown station commander arrived on the scene.The NSRI rescue swimmer was immediately deployed into the water to free dive search an area indicated by bystanders to be where the teenager had last been seen before he disappeared under water and on the second free dive the rescue swimmer located the teenager and recovered him to the surface and then assisted by the rescuers on the shore and assisted by public members the teenager was recovered onto the harbour pier.Advanced Life Support CPR (Cardio Pulmonary Resuscitation efforts) commenced.Sadly after all efforts to resuscitate the teenager were exhausted he was declared deceased.The body of the teenager has been taken into the care of WC Government Health Forensic Pathology Services.Police have opened an inquest docket.Condolences are conveyed to family and friends.The teenager, 18, believed to be from Zimbabwe, was swimming with a family member and friends at the time of the incident.