Nagisaen, Coastal recreational park in Bentenjima, Japan

Nagisaen is a park on the site of a former salt field in Bentenjima, Maisaka-cho, Chuo-ku, Hamamatsu, on the shore of Lake Hamana. It holds tennis courts, baseball and softball grounds, an exercise field, a campsite and the Lake Hamana experience-learning facility Uotto. The grounds were laid out in their present form in the 1960s.

Reclamation work on the site began on 13 December 1946, and a firing ceremony for the salt works was held in March 1947. A fire two months later burned down the salt-making facility, which was never rebuilt and lay abandoned. In the 1960s the land was redeveloped as a large resort project, which failed; the site then received sports grounds and the Lake Hamana experience centre.

Nagisaen became a large open-air concert site: Shogo Hamada played on 20 August 1988, B'z on 31 July and 1 August 1993 and again on 20–21 September 2003, and Southern All Stars on 8–9 August 1998. TUBE performed on 14 September 1996 and ONE OK ROCK on 10–11 September 2016.

Nagisaen is a 10-minute walk from JR Bentenjima Station on the Tokaido Main Line, and about 25 minutes by car from the Hamamatsu-nishi interchange of the Tomei Expressway. The site has parking for 600 vehicles. Facilities include tennis courts, baseball and softball grounds, an exercise field, a campsite and the Lake Hamana experience centre Uotto.

Nagisaen has served as an outdoor concert site: B'z played here on 31 July and 1 August 1993 and again on 20 and 21 September 2003, and Southern All Stars performed on 8 and 9 August 1998. Hamada Shogo, TUBE and ONE OK ROCK also held shows in the park.