Kushiro-Shitsugen National Park (釧路湿原国立公園, Kushiro-Shitsugen Kokuritsu Kōen) is a national park located in the east of the island of Hokkaido, Japan. It was designated as a national park on 31 July 1987. The park is known for its wetlands ecosystems.

Kushiro-shitsugen (Kushiro Wetlands or Kushiro Swamp or Marshland) covers an area of 268.61 square kilometres (103.71 sq mi) on the Kushiro Plain (Kushiro-heiya) and contains the largest tracts of reedbeds in Japan. The Kushiro River (154 kilometres (96 mi)), which originates in Lake Kussharo, meanders through much of the park. During the Ramsar Convention of 1980, in which Japan participated, the park was first registered as a peatland with raised bogs. In 1967, the wetlands (shitsugen) themselves had been designated as a national natural monument. For that reason, access is strictly limited and the landscape, most typical of Hokkaido, has been preserved.

The area was the setting for the 2014 Studio Ghibli film When Marnie Was There.

The vegetation of the park consists of reeds, sedges, peat moss wetlands, black alder thickets. The rivers which bend freely back and forth, groups of lakes and marshes, and other wet ecosystems comprise a varied environment. Kushiro-shitsugen is home to over 600 species of plants. The park is a valuable haven for wild species such as the red-crowned crane (Grus japonensis), huchen (Hucho perryi), Siberian salamander (Salamandrella keyserlingii) and dragonfly (Leucorrhinia intermedia ijimai).

• Kushiro Subprefecture
  • Kushiro, Hokkaidō
  • Kushiro, Hokkaidō (town)
  • Shibecha, Hokkaidō
  • Tsurui, Hokkaidō

• List of national parks of Japan

• (in English) Kushiroshitsugen National Park - National Parks of Japan
• (in Japanese) Kushiroshitsugen National Park - National Parks of Japan
• J-IBIS
• Nature Restoration Project
• Ramsar