Police arrested the suspects at Domsten Harbour outside Helsingborg in a major planned operation.
The police force’s special operations unit and the coast guard were also involved in the swoop.
The six people arrested are suspected of serious drugs crime and were taken into custody in Halmstad.
“They have attempted to smuggle large quantities of narcotics into Sweden,” said police spokesman Christer Harplinger.
Police did not wish to reveal the size of the seizure but Harplinger added that he would not rule out further arrests.