The new Sunday flight is added to the current thrice-weekly schedule, which operate on Tuesdays, Thursdays and Fridays.
The flight will depart Colombo at 1520 hours, arriving in Jeddah at 1850 hours. It will depart Jeddah the same day at 2000 hours and arrive in Colombo at 0450 hours.
The aircraft has 18 business and 296 economy class seats.
"SriLankan is also considering the addition of a third service to Riyadh," the airline said.