The airline will run a winter service to the French city of Lyon, and a twice-weekly service to Lanzarote in the Canary Islands.
An Easyjet spokesperson said the new routes "underline our commitment to the Northern Ireland market".
Airport managing director Graham Keddie said: "We are delighted to welcome Easyjet developing and diversifying their route network from Belfast International."
Easyjet is to fly two new routes from Belfast International Airport.