The gang moved cocaine from South America to Spain, from where it was shipped to Switzerland and Italy, Spanish and Swiss police said in separate statements.
Some 19 people were arrested as part of an investigation that began in November 2002.
Six of the arrests were in Spain including that of the Gambia-born alleged gang boss living in Barcelona.
Twelve arrests took place in Switzerland and one at Italy's Milan airport, they said.
Just over three kilogrammes (6.6 pounds) of cocaine was seized, police said.