Duke Paoa Kahanamoku Lagoon

Duke Paoa Kahanamoku Lagoon is a small, man-made wading pool in the Waikiki neighborhood of Honolulu, on the south shore of the island of Oʻahu near the Ala Wai Small Boat Harbor and Fort DeRussy Military Reservation. The Hilton Hawaiian Village is adjacent to the lagoon.

Source: Wikipedia