Megabus CA operates a bus from Mississauga to Peterborough twice daily. Tickets cost $4 - $6 and the journey takes 15 min. Greyhound Canada also services this route every 4 hours.
How to get from Mississauga to Peterborough
From Erindale GO train to Toronto, train to Oshawa GO, then bus to Crawford Dr. @ Harper Rd. Park & Ride. 3 h 10 min $56. From Mississauga bus to Toronto, ON then bus to Peterborough, ON. 3 h 15 min $38. From Mississauga drive to Peterborough. 1 h 52 min $20.