Glen Erin Trail and Fifth Line Trail are two active transportation routes in Erin Mills, grouped under one designation for historical reasons.

Glen Erin Trail is a paved multi-use trail running through many parks from the corner of Unity Gate and Folkway Drive to The Collegeway just short of UTM. The trail passes through the centre of the oldest part of Erin Mills. It does not receive winter maintenance.

A short section of Fifth Line West, between South Millway and Fowler Court, was spared from the construction of Erin Mills Parkway, and survives today as a quiet street designated as a cycling route. Since 2009, this part of Fifth Line West, along with a connection to Burnhamthorpe Road West via South Millway, has bike lanes.