Wakkanai is the end of the line in northern Hokkaido: Japan's northernmost city, a windy port facing Sakhalin across the Soya Strait. The city is practical and a little bleak, but that is part of its appeal. You come here for edges, ferries, cold seas, and the odd feeling of being closer to Russia than to Sapporo.
Most travellers pass through on the way to Rishiri and Rebun, and those islands are the stronger reason to travel this far. Still, Wakkanai is worth a day if you are already here. Cape Soya gives you the official northernmost-point moment, Wakkanai Park looks over the strait and carries the memory of Karafuto, and the North Breakwater Dome is a strange, beautiful piece of port architecture.
This is not polished resort Japan. The weather can be raw, buses to outlying sights are limited, and winter makes the city feel even more exposed. But if you like frontier ports, sea wind, seafood, and geography made visible, Wakkanai has a grip that more comfortable towns lack.