Sally Minty-Gravett is attempting her fourth crossing, thirty years after she first swam the Channel as an 18-year-old in 1975.
She and Dr Ilse Eiselen left Dover within five minutes of each other on the 25-mile plus swim to Cap Gris Nez, near Calais.
Mrs Minty-Gravett is attempting her fourth crossing in as many decades.
She went into the water first at 5.27 am with husband, Charlie, in her guard boat.
Six hours after they set off Dr Eiselen (29) was about 300 yards ahead as the pair crossed the busy Channel shipping lanes.
Mr Minty-Gravett reported that conditions were good with a flat calm sea, little wind and a water temperature of 18 to 19C.
