underwater park; marine park
Refers to a protected marine area where visitors can observe underwater life, often through glass-bottom boats or diving. Common in contexts like national parks or tourist attractions.
I saw colorful fish at the underwater park in Okinawa.
This area is designated as a marine park.
海洋公園 is a broader term for 'marine park' that may include coastal land areas, while 海中公園 specifically emphasizes the underwater environment.
Compound of 海中 (かいちゅう, 'in the sea') and 公園 (こうえん, 'park'). The term is a straightforward modern coinage for designated marine conservation and recreation areas.