A famous hike is the walk from Fira to Santorini. The walk can be done in 3-4 hours and brings you along the rim of the Caldera. Following the road is an alternative as a cyclist.
Park your car in the public parking station in Fira close by the cable car and walk up to the cable car station. This is where you start walking along the Caldera to Oia.Maybe one of the most famous walking paths in the world.