There are 3 sister-cities and a lot of friendship cities and towns through various interests.
Ranua - Iwasaki village, Aomori pref. (1990)
- Santaland Shirakami
Jyväskylä - Niiza city, Saitama pref. (1997)
Kalajoki - Izumo city, Shimane pref. (2003)
Vihti - Fukui prefecture (1980)
- Fukui Prefecture Youth Ship
Oulunsalo - Tanno town, Hokkaido (1992)
- Oulunsalo Music Festival
Kemijärvi - Sobetsu town, Hokkaido (1993)
- snow fight
Housjärvi - Naie town, Hokkaido (1995)
- social welfare
Oulu - Sendai city, Miyagi (2005)
- industrial development
