| Saikai National Park | |
|---|---|
| 西海国立公園 | |
 Kujūku Islands | |
  Saikai National Park Location of Saikai National Park  Saikai National Park Saikai National Park (Japan) | |
| Location | Nagasaki prefecture, Japan |
| Nearest city | Sasebo, Hirado, Fukue |
| Coordinates | 32°40′11″N 128°37′38″E / 32.66972°N 128.62722°E |
| Area | 246.46 km2 (95.16 sq mi) |
| Established | March 16, 1955 |
| Governing body | Ministry of the Environment (Japan) |
Saikai National Park (西海国立公園, Saikai Kokuritsu Kōen) is a marine national park located in Nagasaki prefecture of northwest Kyūshū, Japan. It consists of the coastal regions of Matsuura Peninsula, extending northward from the port city of Sasebo and encompasses the Kujūku Islands, with over 200 islands to the west, Hirado Peninsula further west, and the coastlines of the Gotō Islands to the far west.