The 49-year-old New South Wales man was arrested in a caravan where officers allegedly found 320 kilograms of cocaine in 320 individual blocks.
The cocaine haul is worth at least $128 million.
Police believe the drugs were destined for Western Australia and other Australian states.
It will also be alleged that the 37-year-old German citizen flew to Australia in early May to help recover the cocaine.
“She allegedly met a 49-year-old New South Wales man in Port Hedland and the couple traveled to Karratha, some 150 miles away, where they chartered a 21-foot boat,” the Australian Federal Police said in a statement. .
“It was driven to Port Hedland before being launched from a local boat ramp and headed some 17 miles out to sea on Thursday and Friday nights.
“Police suspect the couple used the vehicle to collect cocaine from the ocean off the Pilbara mining town.”
The boat allegedly used by the men was seen idling near an international carrier and police are now investigating whether the boat was used to import drugs into Australia from abroad.
AFP Acting Deputy Commissioner John Tant said the arrests should send a “strong message” to organized criminals looking to import illegal drugs into the country.
“Australia is not a safe haven for criminals. We are going to hunt them down and we will not stop,” he said.
“This quantity of cocaine could have been sold to around 320,000 Australians as if it had been broken down into street level one gram deals and put around $128 million into the pockets of the criminals involved in its distribution.
“We know that drug trafficking can lead to drug wars on our streets, and often law-abiding citizens can be the collateral damage of that violence. Illicit drug trafficking can also fund other heinous crimes, such as human trafficking. of persons and sexual servitude”.