Iberia is to use its new Airbus A330-300 fleet to operate its Madrid-Luanda route.
The IAG-owned carrier flies a twice-weekly service between the Spanish and Angolan capitals. Its A330-300 widebodies are configured with 36 flat-bed seats in business class and 242 seats in "tourist" class.
Use of the A330-300 on services previously flown with A340-400s will bring an 11% increase in seat numbers, says the airline.
Iberia's traffic on the route - which it has operated since October 2011 - grew more than a third in 2013's first half.
Flightglobal's Ascend Online database shows that the airline has taken delivery of four A330-300s so far this year.