The B3415 covers most of the former route into Fowey of the A3082 (formerly B3271) south of Newtown crossroads.
The Newtown crossroads is actually a mini-roundabout and the B3415 heads southeast from here across the fields before turning eastwards as it enters Fowey. The road becomes residential and crosses a couple of mini-roundabouts before descending the steep and narrow New Road Hill. As the road widens and levels out a sign advises of congested streets ahead and so the road bends to the right towards the town's car parks. However, the B3415 TOTSOs left to end almost immediately afterwards at the next road junction, with the road ahead unclassified. The A3082 followed the narrow Lostwithiel Street into the town centre and met the B3269, although going this way on foot will make it obvious why the road is now unclassified.