Japan's exports in September rose 16.7% from a year earlier, missing market expectations by a huge margin. Reuters-polled analysts had pegged exports growth at 20.1%.
This is the second straight month that shipments from Japan have recorded a slowdown, after hitting a near four-year high in July.
Growth was supported by continued strong semiconductor exports, with shipments rising 49.4% year on year by value.
Exports of machinery also bolstered growth, with semiconductor-related machinery shipments up 43.9% and power generation machinery exports climbing 22.6%.
In terms of destinations, shipments to mainland China — Japan's largest trading partner — rose 8.6%, while exports to the U.S. climbed 22.9%.
Exports have been the main driver of Japan's growth for the first two quarters of 2026, helping the world's fourth largest economy beat expectations in the first quarter, and supporting growth in the second.
Japan's imports in September grew 18.9%, also missing expectations of 19.6% from Reuters.
Tokyo's imports of petroleum climbed 51.1% by value in September, with inbound shipments from the U.S. surging nearly 820%, while those from the Middle East inching up just 1.5% as the conflict in the region continues to impede supplies.
Following the data release, the benchmark Nikkei 225 was up 1.8%, while the Topix gained 1.14%.
The data comes as the Bank of Japan is set to meet next week, and Reuters poll estimates indicate that the central bank is set to hold its policy rate steady at 1%.