The cocaine drug cartel, based in the Madrid suburb of Alcala de Henares, use drug mules who injest pellets filled with drugs and avoid detection at airports, the police said in a statement.
Police seized about 18 pounds of cocaine and 17,000 euros in cash as part of their investigation, which began in September 2011.
The majority of those arrested were Nigerian citizens.
Police carried out their first arrest as part of the operation in October 2011 at the airport at Palma de Majorca of a man who had swallowed 77 pellets of cocaine.
Later that month police detained another man at the same airport who had swallowed 68 pellets of cocaine.
“These people had been sent by the organisation to Madrid to collect cocaine from other members of the ring which based in Alcala de Henares. From there they would also send mules to South America and Africa to collect the drug,” a police statement said.