Authorities say the four men were reported missing on Wednesday night during a heavy storm.
Three Spanish tourists have died and another man remains missing after a "terrible canyoning accident" in northern Switzerland.
Police in St. Gallen said the four men had been reported missing on Wednesday night during a heavy storm.
"They were together on a canyoning tour in the Parlitobel Gorge and must have been surprised by the storm," according to a police statement.
A large number of rescue workers were deployed and authorities were able to recover three bodies overnight but had to break off the search for the fourth missing man due to adverse weather.
The search had resumed in the early hours on Thursday. The four men have not been identified.
Canyoning is a popular activity among tourists for crossing gorges by climbing, swimming or abseiling.
The Parlitobel gorge in Sarganserland drops from 3,107 metres above sea level to 1343 metres and the region is described on local websites with “multiple worthwhile canyoning tours”.
In July 1999, 21 people were killed during a canyoning accident in the Swiss Alps near Interlaken when their guided tour was swept up by sudden rainfall.