The simplest way to get from the airport to IMT Atlantique's Rennes campus is by taxi.
However, it is also possible to take bus number 57 at the "Air Libre" stop, 300 metres from the terminal.
Bus 57 will take you to the centre of Rennes (the "République" stop) in 20 minutes, every day of the week.
The bus stop closest to the airport is at the intersection of Avenue Joseph Le Brix (the street the airport is on) and Avenue Jules Vallès, 300 metres from the terminal.
Buses run throughout the week, including weekends and public holidays.