Thai Airways International has contracted British Airways Engineering to provide it with line maintenance services at London Heathrow.
Maintenance will be carried out by BA's customer engineering division at Heathrow's Terminal 3, which Thai Airways serves twice-daily with Boeing 747-400 aircraft.
The agreement between the two carriers is reciprocal and from 12 November Thai will provide technical services for the aircraft deployed on BA's Bangkok flights.
BA's line maintenance services for Thai Airways will begin immediately.
The deal is in line with BA's strategy to increase the amount of third-party maintenance work it provides to other carriers. External work accounts for about 10% of BA's engineering revenue.