The public prosecutor in French Polynesia said the sailors who had 500 kilogrammes of cocaine hidden in their catamaran claim they didn't know about their cargo.
Their boat was searched after it arrived in Nuku Hiva in the Marquesas islands at the weekend.
Police seized the drugs and flew the three men - two Dutchmen and a Pole - to Papeete for questioning.
Initial media reports said three had sailed from Venezuela with 400 kilogrammes of cocaine onboard.
Now the news agency AFP says the catamaran had sailed from Costa Rica with 500 kilogrammes of cocaine, which the prosecutor says was probably destined for the Australian market.
This year more than two tonnes of cocaine have been seized on yachts stopping in French Polynesia.