The incident occurred around 3.30pm on Wednesday when the driver lost control of the bus for reasons not immediately known and collided with the base station of an older mountain lift, Obwalden cantonal police said.
Eight of the tourists and the tour leader suffered moderate injuries and were transported either by ambulance or Rega emergency rescue helicopters to hospital, police said in a news release.
The driver, who was wearing a seatbelt, was uninjured, the release said.
The other 30 passengers — all Chinese tourists — were transferred to a local hospital for checks.
The Engelbergerstrasse was closed for two hours while the passengers were evacuated.
The bus was a complete write-off and has been subjected to a mechanical check, Obwalden police said.
The Chinese Embassy was informed of the accident and an investigation into its cause is under way, police said.