Exports totalled 127.9 billion euros ($134.5 billion), a decline of 1.2 percent on the previous month, according to figures from federal statistics agency Destatis.
Analysts surveyed by FactSet had predicted a smaller dip of one percent.
Imports were down 0.4 percent compared with July, totalling 111.4 billion euros.
The country’s trade surplus — the difference between exports and imports — rose slightly to 16.6 billion euros.
“Like the rest of the German economy, exports remain stuck in the twilight zone between recession and stagnation,” said ING bank economist Carsten Brzeski.
The August disappointment was led by a 2.6-percent fall in exports to fellow eurozone countries.
Shipments to the United States, the top destination for “made in Germany” goods, dipped by 1.3 percent month-on-month.
High inflation, an industrial slowdown and weaker demand from key trading partner China have all been weighing on Europe’s economic powerhouse in recent months.
The German economy tipped into a recession at the start of the year and stagnated in the second quarter.
A slew of weak economic data since then suggests the country has remained stuck in the doldrums.
“The risk of the German economy of sliding back into recession in the third quarter remains high,” said Brzeski.
Germany’s leading economic institutes said last week they expect gross domestic product to contract by 0.6 percent in 2023.
The International Monetary Fund has predicted that Germany will be the only major advanced economy to shrink this year.