Besides the Indians, the divers were Iranian and Ukranian.
An Iranian official said the diving chamber in which they were trapped had limited supply of oxygen but the rescue team hopes to reach them soon.
Pirouz Mousavi, head of the Pars Energy Zone in southern Iran said the divers have been trapped in the diving chamber of the sunken ship which has oxygen for 48 hours.
"So we are hopeful that they will be saved," he was quoted as saying by IRNA news agency.
Sixty people on board the Iranian ship that sank in the Persian Gulf on October 20 have already been rescued and rescuers are looking for the missing 13.
The ship was reportedly heading towards southern Assaluyeh Port from the nearby oil platforms when it sank 15 miles away from the harbour due to an overload of cargo.