Surname Rumbai (Rumbai 
) , in the world, is a rare family name. The family name Rumbai is habitual in Indonesia, where it is a very rare surname, Malaysia, where it is an extremely rare surname, and Argentina. Not in comparison with a country's population, it is the most numerous in Indonesia, Malaysia, and India. Very seldom, Rumbai is the forename as well as the last name.