Corsica Linea rescued the migrants off the Balearic Islands and disembarked them in Majorca.
Corsica Linea, a French passenger ferry company, announced on Monday that it had rescued 18 migrants in the Mediterranean Sea.
The ferry rescued the "18 shipwrecked (migrants) off the Balearic Islands," the company's Director-General Pierre-Antoine Villanova revealed on Twitter.
"Corsica Linea fulfilled its ship-owner's duty by respecting international conventions, the Spanish state did the same when it welcomed these shipwrecked. Congratulations to the ship's sailors for their actions," he added.
The ferry had left Alger on Sunday and was heading for Marseille with 2,000 passengers on board.
Pascale Albertini, a spokesperson for Corsica Linea, told the AFP news agency that the migrants had been in good health and that they were dropped off in the port of Alcudia, on the Spanish island of Majorca.
Migrants attempting the perilous sea voyage between North Africa and Europe have, in the past, been rescued by private fishing vessels or tankers. Most, however, have been rescued by NGOs.
In 2017, non-governmental search and rescue (SAR) operations picked up 9,000 migrants in the Mediterranean according to Blaming the Rescuers, which denounces cuts to the European Union-funded SAR operations and the criminalisation of their NGOs' activities in the Mediterranean by some EU states.
On Monday, the Eleonore rescue ship from the German Mission Lifeline NGO was seized by Italian authorities for breaching a ban to enter the country's territorial waters.
The NGO said in a statement it was forced to enter Italian waters after a thunderstorm and heavy rains flooded the boat's deck. The ship's captain and his first officer were taken away by police while the 104 migrants were taken to a "sealed-off camp."
An estimated 60,040 migrants have reached Europe so far in 2019, according to the United Nation's High Commissioner for Refugees (UNHCR).
Over two-thirds (48,873) of them arrived by sea while 894 are dead or missing.