Despite being a widespread and important ungulate in wetland ecosystems, scientifically applicable information of sika deer Cervus nippon do not exist in Japan. Understanding seasonal movement of deer will not only clarify habitat use, it will also lead to better management and conservation of wetland ecosystems. Kushiro Shitsugen National Park (KSNP) is the largest wetland ecosystem in Japan, located in the eastern part of the northernmost island of Japan, Hokkaido. The objectives of this study were to document fine-scale movements of female deer and determine effects of snow cover and hunting pressures on movements in KSNP. Wetland makes up 94.8% of KSNP (forests 3.4%, grassland 1.6% and urban and suburban 0.2%). Thirty-two female sika deer were equipped with GPS collars to clarify their seasonal movement and habitat use during snow cover (SC) and non-snow cover (NSC) seasons from October, 2014 to March, 2016. We calculated 50%-core home-range (LoCoH) and determined movement patterns. Deer were primarily crepuscular. We also calculated Manly’s selection index, and concluded that wetland was the most-used land type, but deer preferred forest, urban and suburban, and grassland landscapes over wetland during both SC and NSC. Over 60 % of deer used only KNSP and never migrated to outside of KSNP. About 28% of deer used KSNP only during SC and the hunting season. The study results showed KNSP was used by sika deer to avoid hunting pressure.