ZURICH—Switzerland is buying back its own luxury watches from abroad at an increasing rate, a report Thursday showed, as the industry grapples with weaker global growth, slowdowns in parts of Asia and reduced tourism in Europe.

Of the 3.3 billion Swiss francs’ ($3.28 billion) worth of watches imported into Switzerland in the first 10 months of 2016, 1.3 billion francs, or 40%, had previously been exported out of the country, according to a report from the Swiss federal customs office. Swiss watch exports totaled nearly 16...