Negotiations between the owner Massoel Shipping and the kidnappers led to the release of seven Filipinos, a Bosnian, a Croatian, a Romanian, a Slovenian and a Ukrainian, all of whom were then flown to Switzerland, ATS news agency and the Basel prosecutor's office said.
The ship, MV Glarus, and its cargo of wheat are still in the hands of pirates who attacked on September 22nd and destroyed most of its communications equipment.
It was not known whether a ransom was paid for the crew's release.
As previously reported, the ship had been transporting wheat from Lagos to Port Harcourt, in southern Nigeria, when it was hijacked off Nigeria's Bonny Island.
German-language newspaper Blick reported that the pirates belonged to the Movement for the Emancipation of the Niger Delta (MEND), which says it wants the region's population to receive a bigger share of the country's oil and gas revenues.