The divers from nautical brigades in Agde (Hérault) and Grau du Roi (Gard) will search water-holes in ten areas identified in the vicinity of the village, according to a report in the Midi Libre daily.
As the search for the teen entered its fifth day, volunteers and police continued to scour the terrain in the countryside east of Barjac. The volunteers have been divided into groups of 5 to 6 people, the newspaper reported.
The search has been extended nationwide for the teenager who disappeared in mysterious circumstances on Friday afternoon.
The 15-year-old apparently vanished without trace at around 5.30pm on Friday. Her moped was left at a friend's house some 10 kilometres from her home.
The vehicle was found at around 10pm with a cold engine.
The girl is described as being 1.59 metres tall, with a slim build, blue eyes, long light brown hair and pierced ears. At the time of her disappearance she was wearing jeans and a beige Adidas jacket with black sleeves.
Police in Barjac have called for any witnesses to contact a hotline on 04.66.24.50.27.