Nagai Uminote Park Soleil Hill, Public park in Yokosuka, Japan.

Nagai Uminote Park is a recreational area built across rolling green hills in Yokosuka, featuring cultivated gardens and open spaces. The site offers views toward Sagami Bay and Mount Fuji on clear days from various vantage points throughout the grounds.

Most of the park occupies the site of the former Imperial Japanese Navy Second Yokosuka Air Base, completed just before the end of the war and barely used. After 1945 it served as a US military helicopter base, housing and wheat fields, and was returned to Japan in 1985; part is now an Air Self-Defense Force radar site. The park opened on 29 April 2005 and reopened on 14 April 2023 after renovation.

The park's nickname Soleil means "sun" in French, and its design borrows from Provence, with cobbled paths and brick buildings. Visitors can join craft and cooking workshops, meet animals at the Animal Village, and ride the Soleil Train, formerly the Choo Choo Train. The site also holds a firefly house, Hotaru-kan.

The park can be reached via the Keikyu Electric Railway to Misakiguchi Station, where a direct bus service connects to the main entrance. The bus route is straightforward and provides easy access from the train station.

Most of the park occupies the site of the former Imperial Japanese Navy Second Yokosuka Air Base, completed just before the war's end and therefore barely used. After 1945 it served as a US helicopter base and housing before being returned to Japan in 1985; part is now an Air Self-Defense Force radar site.