Onuma Quasi National Park (大沼公園, Ōnuma Kōen) is a great destination for a day trip from Hakodate. The park's main attractions are the islands that dot the many lakes with the majestic Komagatake volcano in the backdrop. It is surely a great destination for a sunny day; therefore I was pretty disappointed when I arrived there in a cloudy and unwelcoming weather.
The place offers various easy hikes that hop from one island to the other. Once I started walking in the almost deserted area I really started to enjoy it. The lack of any other people turned it from what would have been a crowded place, into an immersion in nature. There was no other noise than the wind blowing through the branches and the cawing of the ever-present ravens. The view of the sea of clouds swirling past around the hidden summit of Mountain Komagatake is majestic.
The biggest islands are connected by several bridges and there is a network of paths covering the whole area. You will walk by moss-covered plains and lush forests while enjoying the view of the surrounding lake. Although surely not the best conditions for a hike, the experience was still very pleasant and relaxing. Furthermore in summer you will also find wide areas covered in blooming water lilies and, if you are lucky, you could even spot some chicks hurrying behind their mother.
From Hakodate it takes 1 hour (¥540) by local train or 45 minutes (¥1160) by Limited Express. The park is a 3 minutes walk from the Onuma-Koen JR station.