The main tour (Red Line) runs around the edge of the city centre taking in the Venetian harbour and city walls before heading out to the palace of Knossos.
From Knossos the service returns into town and serves the main square in the centre of town
An alternative Blue Route deviates from the red line at the sea end of the city walls and runs out to some of the beaches west of the city before re-joining the original tour route around an hour later at the first gate in the wall. The blue tour takes around 2 hours
A multi-lingual live commentary tells you about the key sites.