The stash of cocaine was uncovered in a shipping conainer by Italian authorities last month as part of a wider operation to disrupt international drug traffickers.
The suspects were arrested at a rental home near the northern city of Thessaloniki on drug smuggling charges.
A gun, wads of cash and walkie-talkies were also discovered.
👮Περίπου 300kg κοκαΐνης κατέσχεσαν αστυνομικοί της Διεύθυνσης Ασφάλειας Θεσσαλονίκης σε συνεργασία με το γραφείο D . E . A Αθηνών και με τη συνδρομή της @GDF.
◾Οι ουσίες εισάγονταν σε κοντέινερ με μπανάνες από χώρα της Λατινικής Αμερικής. pic.twitter.com/L3qmZCnv8i
— Ελληνική Αστυνομία (@hellenicpolice) June 10, 2022
All four are men aged 38, 45, 48 and 52.
They are residents of London and Liverpool but police did not give any further details of their identities.
A video showed the four men, one of whom appeared to have his face covered, handcuffed and being led into a building.
A fifth British man, believed to be outside the country, was also wanted for questioning, police added.
The arrests followed an international law enforcement operation that also involved Italian customs authorities and the US Drug Enforcement Administration, Greek officials said.
The seized drugs had been bound for other European countries and Australia, they added.