The dolphins, three males and two females, are expected to be delivered to the Crimean city of Sevastopol, the home base of the Russian Black Sea fleet, by August 1, 2016.
Contract documentation details that all animals should be between three and five years of age, have perfect teeth, and be in good physical condition.
According to an unnamed source speaking with RIA Novosti, the dolphins will serve in the framework of Russia’s new maritime military program, in development since 2014.
"Americans looked into this first," Viktor Baranets, a retired Russian colonel, said of the practice of using dolphins for military purposes. "But when Soviet intelligence found out the tasks the US dolphins were completing in the 1960s, the defense ministry at the time decided to address this issue."
Soviet military dolphins were highly skillful, and could plant explosive devices on enemy vessels and detect abandoned torpedoes and sunken ships, Barents said. But after the dissolution of the USSR, all sea mammals in service were reportedly sold to Iran.