Tax officials and police carried out the raid on the cargoship Lady Boss off Almeria on Tuesday. Of the arrested men, 11 were Ukrainian, many from Odesa, and two were Bulgarian, local media said.
Law enforcers found 18 tonnes of the drug in 600 bales.
The vessel had been observed for a week. It has been taken to the seaport of Almeria. AIS data shows its next destination as Egypt.