Air China is switching London flights to Chengdu from Gatwick to rival Heathrow.
The change from April 2 comes after just a year of operations from Gatwick.
The airline said Heathrow offered passengers “a more efficient and convenient flight experience”.
The carrier has been operating the route since July 3, 2018 carrying almost 30,000 passengers.
Air China’s three Airbus A330 flights a week on the route will run from Heathrow Terminal 2.
Air China’s wholly-owned subsidiary Shenzhen Airlines started a direct route from Heathrow to Shenzhen in October, with three flights a week.
Air China UK general manager Jingjie Li said: “After near a successful year of flying to and from London Gatwick, the move in terminals will ensure that our long-distance route between London and Chengdu heightens our passenger’s enjoyment making their continuing journey into London easier and more convenient.
“We are also excited to announce that our direct service between London and Beijing will be increasing to three daily flights.
“As the national flag carrier of China and a member of Star Alliance, we are continuously looking for ways to improve our services and flight routes between the UK and China.”