After completing more than 200 dives over a period of 18 days, he said the group were "euphoric" at the find, and called for a fuller investigation of the site.
Claims of the discovery of a submerged 1,000 year-old temple beneath the waters of Lake Titicaca have sparked controversy in Bolivia.
An international group of archaeologists say there is evidence of a temple 200 metres long and 50 metres wide, along with signs of a paved road.
The holy site is thought to be from a civilization even older than the Incas - possibly the ancient Tiwanaku culture.
However the claims have been met with concern from local people over what they see as intrusive investigations into one of the most holy parts of the Andes.
'Conclusive proof'
Eduardo Pareja, a Bolivian scientist who was among those who explored the site, said the remains provided "conclusive proof" of the existence of a pre-Columbian temple.
After completing more than 200 dives over a period of 18 days, he said the group were "euphoric" at the find, and called for a fuller investigation of the site.
However, Bolivian archaeologist Dr Carlos Ponce is skeptical about the real significance of the find, and says the expedition has yet to provide any concrete proof.
He points to 12 previous expeditions in Lake Titcaca, including one by French explorer Jack Cousteau in 1968 in a submarine - which revealed nothing.
Superstition
Local communities, some of whom are very superstitious, regard the expeditions with suspicion, fearing they will only bring bad luck.
"We think it's a bad sign, and maybe in the future there will be some accidents because people didn't respect the lake", warns Javier Crespi, from Copacabana, one of the towns bordering Lake Titicaca.
However the possible discovery of the underwater remains of a 1,000-year old civilization only adds to the aura of legend and mystery which surrounds Lake Titicaca, and is likely to attract more and more sightseers to what is already Bolivia's prime tourist attraction.