Originally Posted by keihin_242

If you're looking in July, August, and September, that is peak travel season for Japanese tourists in Hokkaido and the ANA/JAL duopoly maxes out revenue accordingly. The Sapporo Snow Festival in February also drives prices up. If you don't mind going when it's cold and snowy, look at early to mid-December for the cheapest airfare and hotels. Prices start to fall October 1 as that is when the unofficial Hokkaido travel season ends.

Also, avoid Japanese holidays. Even one day off will drive airfares up.

It's also helpful to know HND-CTS is the busiest air route in the world and the Shinkansen isn't able to drive prices down because even with the tracks going all the way to Hakodate the Shinkansen just isn't fast enough to compete with the airlines to Sapporo. Hadodate airport does appear to be a little less expensive than CTS, though. Not sure if that's enough to make a difference from Taiwan.