AIRMauritius is increasing ex-UK capacity by 30% from November 6.
The addition of a third non-stop Heathrow service to Mauritius on Saturdays will complement existing Friday and Sunday flights.
All three of the flights are on Airbus A340 aircraft seating 301 passengers.
The airline also operates a weekly non-stop flight from Manchester every Monday. A 181-seater Boeing 767 flies on this ex-UK route.
Regional manager UK and Ireland Chris Gilbert said the additional flight was the first step in a plan to increase the number of seats out of the UK.
He said: “This third service from Heathrow means we are now beginning to achieve the levels of capacity we currently desire from the British market.”
The capacity increase allows Air Mauritius to match British Airways’ thrice-weekly Gatwick flight.
Gilbert said Air Mauritius’ UK growth would also help tourism to the island as the three non-stop services over the weekend were timed to meet operators’ needs.