Stockholm, Porto and Zagreb have been added to the network, and an additional aircraft will be based at Manchester
The new flights will be available to book from midday on Thursday September 15 for travel from April 28.
To celebrate the launch of these new routes prices will start at £33.
Birmingham, Manchester and Luton will serve Stockholm, Gatwick and Manchester will serve Zagreb and Luton and Manchester will serve Porto.
As well as the three new destinations, Monarch has now put Birmingham-Nice, Luton-Arrecife and Luton-Rome on sale and has added frequencies to popular destinations for summer 2017 including Lisbon, Barcelona and Rhodes.
Marjan Schoeke, Monarch’s head of network development, said: “Flights to Stockholm, Zagreb and Porto will operate all year round and we are sure that all three destinations will be a popular choice with our customers.”