Thi Tran, 45, and Manh Dao, were arrested two years ago after a routine police patrol in the park of a Melbourne suburb.
The couple was thought to be acting suspiciously when police saw them walking away from a black BMW as soon as they saw them. Police had just finished a separate investigation into drug trafficking, when the search of the vehicle uncovered 25.2 kilos of high-purity heroin and 6.6 kilos of methamphetamine plus $160,000 in cash.
Police estimated the drugs to be valued at more than $47 million on the street.
The couple first fought the charges, then pleaded guilty to one charge of trafficking a large quantity of drugs. They refused to give any information regarding where or from whom they got the drugs.
The pair will spend at least 13 years in prison.