The eurozone's current account surplus slumped to 800 million euros ($1.02 billion) in September from 10.9 billion euros the previous month, European Central Bank data showed on Friday.
The current account on the balance of payments, which includes imports and exports in both goods and services plus all other current transfers, is a closely tracked indicator of the ability of a country or area to pay its way in the world.
It is crucial for the long-term confidence of investors and trading partners.
Over the 12 months to September, the current account showed a surplus of 77.8 billion euros, compared with a deficit of 7.6 billion euros in the corresponding period a year earlier, the data showed.
In Brussels, the Eurostat statistics agency said the 17-nation eurozone had a trade surplus of 9.8 billion euros in September, after 5.2 billion euros in August and compared with 1.7 billion euros in a year earlier.
September eurozone exports fell 1.1 percent from August while imports were down 2.7 percent, it said.
For the 27-state EU, the trade balance was in deficit of 12.6 billion euros in September, a slight improvement from 13.2 billion euros in August and compared with a deficit of 10.9 billion euros a year earlier.
September EU exports dropped 1.5 percent from August and imports were off 1.7 percent.