Authorities in Thailand intercepted more than 193 kilograms of amphetamine hidden in punching bags bound for Australia where it would have a street value of almost $30 million.
The drugs, packaged in bags each weighing more than 10 kilograms, were hidden in 15 punching bags.
Officials told a news conference the shipment was inspected by Thai customs after authorities grew suspicious since the Thai-made boxing training tool is not in high demand in Australia.
They did not provide details of when the drugs were seized.
Both Thai and Australian authorities are working together in the investigation.