The coins were discovered during raids yesterday by the police at properties in Enfield, in north London, Essex and Hertfordshire. Two vehicles in Essex were also searched.
It is thought to be the biggest recovery of fake coins in the UK, the BBC reported.
The arrested men, aged 27, 43 and 52, face money laundering and counterfeiting charges. The police did not name the men.
The haul included four million blank coins apparently due to be turned into pound coins, and 107,000 pounds in completed counterfeits.
