It is down to a pilot shortage, the airline says.
It could see up to an average of 15 flights cancelled daily.
Air passenger rights company AirAdvisor says it could impact up to 50,000 UK travellers.
This includes those with connecting and indirect itineraries.
SWISS operates flights out of UK to London Heathrow, London City, Manchester and Edinburgh.
Anton Radchenko, founder of AirAdvisor, said: “With this latest wave of SWISS cancellations, summer just got more complicated for UK travellers. We’re not seeing a demand problem but a staffing and scheduling bottleneck.”
“Flights are getting axed not because people aren’t flying, but because airlines don’t have enough fully trained pilots.”
Customers on cancelled SWISS flights can get a full refund and free rerouting.
“We regret that we are unable to offer the affected connections as originally planned. In such cases, we inform the affected customers as early as possible,” the airline said.
“Schedule adjustments are made as far in advance as possible to minimise inconvenience and to find the best possible alternative travel solutions.”