Vietnam Airlines is adding a fifth weekly service from Gatwick during the summer, increasing its Ho Chi Minh City route from two to three times a week.
The airline will also continue to serve Hanoi twice a week.
With around 100,000 UK holidaymakers travelling to the country each year, the airline says arrivals have risen by more than 40% year on years since its first nonstop service was introduced.
David Cook, sales manager UK, Vietnam Airlines, said: "We are very encouraged by the positive results so far, and are now trialling additional frequency in the summer months to gauge market response, with a view to possible future expansion into 2014."
Relations have grown rapidly between the UK and Vietnam, with the two countries signing a Strategic Partnership Agreement in 2010 to help boost bilateral trade, economic ties and investment.
