Easiest way to get to Hossa is by plane. Closest railway station is in Kontiomäki, 170 kilometers from Hossa so flying makes travel arrangements a whole lot easier and more convenient too. Kuusamo airport (KAO) is only 80 kilometers away, Kajaani airport (KAJ) 200 kilometers away and the distance to Oulu airport (OUL) with the most variation between flight schedules and operating airlines is 250 kilometers. Flight from Helsinki (HEL) to one of these airports takes approximately one hour.
The circumstances change a lot depending on the time of year and therefore travel times vary but in general everything works very well no matter the season. Distances are fairly short and the whole area so sparsely populated that rush hours and intense traffic are things we have never even heard of!
The Hossa national park area and actually the whole Kainuu region is a unique place because here you can really feel that you are in the middle of nowhere and surrounded by nature and at the same time, all of the natural wonders and activities are easy to reach because of the modern, very well maintained infrastructure.