Otaru Canal walk is a must once you explore Otaru.

Otaru Canal is a compact, picturesque stretch of restored warehouses and gas lamps right by the port, so plan to arrive on foot from Otaru Station in about 10 to 15 minutes and leave time to stroll the waterfront and nearby Sakaimachi shopping street. Go early morning for quieter photos or at dusk when the lamps and reflections make the best pictures, and expect crowds in the middle of the day; boat tours run mainly in spring to autumn and take about 20 minutes if you want a short guided view. In winter the canal is beautiful with snow and lighting displays, but bring warm layers and grippy shoes because paths can be icy, and remember the walk is free while boat rides and museum entries cost extra.