Overall, sales in Asia were down by 21.4%, with China responsible for most of this decline.
Consumers in the world's second largest economy bought nearly 40% fewer Swiss watches than it did last year.
However, the figures from the Federation of the Swiss Watch Industry do not take into account the recent
yuan devaluation in China.
The weaker currency will make imports more expensive for the Chinese, which is likely to dent watch sales further.
This, together with the fact that the Chinese stock market has lost nearly a third of its value since early June, is expected to continue to weigh on demand in the coming months.
Swiss exports this year were hampered by the Swiss central bank's decision to abandon its currency ceiling with the euro in January.
This decision caused the franc to rocket in value, making exports from Switzerland relatively more expensive.