Japan's exports fell 9.2% in October from the year before, the biggest drop in three years and threatening to tip the trade-reliant economy into recession. Experts had predicted a 7.6% drop.
Imports also slumped nearly 15%, resulting in the country's first surplus in four months.
The weaker trade data reflect lower oil prices but also plummeting shipments of cars and aircraft engines to the US and plastic materials to China.
Exports to the US dipped 11% from a year earlier in the third straight month of declines and imports from the US fell 17% year-on-year.
Shipments to China, Japan's biggest export market, dropped 10%.
Two-way trade with South Korea fell 41% in October, with both exports and imports falling as relations languish at their worst level in decades.
Overall, imports totalled 6.56 trillion yen ($60.5 billion) while exports were 6.58 trillion yen ($60.6 billion), leaving a trade surplus of 17.3 billion yen ($159 million).
As trade with the world's two largest economies slips, Japan is turning to the United Kingdom. Japanese Economy Minister Yasutoshi Nishimura said on Wednesday that he hoped the UK would join the Trans-Pacific Partnership after it leaved the European Union.