The hostages included two Russians and a Romanian, the Russian news agency RIA Novosti reported.
Carisbrooke Shipping, the British owner of the MV Esther C, said pirates boarded the ship Thursday in the Gulf of Guinea.
The company said the ship was proceeding on its way by Saturday.
"Having stolen personal possessions, the pirates departed the vessel taking three crew members as hostage," Carisbrooke said in a statement.
While piracy in the Indian Ocean by crews based in Somalia has received more publicity, the International Chamber of Commerce said West Africa is one of the most dangerous places in the world for shipping.