BEIJING, Oct. 14 -- China's customs service reported Wednesday that the country's goods trade passed 5 trillion yuan in a single month for the first time, and that the fastest growth among its main partners is coming from Southeast Asia, not the United States.

The General Administration of Customs put September trade at 5.16 trillion yuan, about $771 billion, up 27.5% from a year earlier. Exports came to 3.03 trillion yuan, up 29.6%, and imports to 2.13 trillion yuan, up 24.6%. It was the sixth straight month of double-digit growth.

The split by partner is less even than the total. Over the first nine months, trade with ASEAN grew 22.7%, trade with the European Union 8.4% and trade with the United States 4.1%. That gap sits beside the U...