Kewalo Basin is a boat harbor between Honolulu Harbor and the Ala Moana Beach Park. Fishermen moor there, as do charter, excursion, and dinner boats.
We first saw Kewalo Basin in "24 Karat Kill" (Season 1). There, Johnny Fargo (Kaz Garas) moored his tuna fish boat, the Alika. That's a name we would hear again in later seasons, when Tony Alika (Ross Martin) came to rule the Kumu. McGarrett interviewed Fargo on the dock, then went into the Cocktail Bar, seen just right of the Fisherman's Wharf restaurant, and interviewed barkeeper Al (Mark LeBuse), who said he couldn't tell McGarrett any more about Fargo even if he paid for the full aloha dinner.
Fargo seemed to have picked up an idea for a dish called tuna stuffed with gold (Is that a dish?). He hid gold imported from Japan in the fish he caught until he could get it past the authorities, then removed the gold for use by crooked lawyer Dennison (Paul Richards) before selling the fish at the Honolulu Market. The scheme worked until a fish was sold with the gold still in it.
When Dennison ordered his henchman to kill a young mother in order to recover the gold, he bit off more than he could chew, namely Five-0, the Treasury Department under soon-to-be Governor Jameson (Richard Denning), and Federal agent Andrea Claire Dupre (Marj Dusay). McGarrett arrested Dennison in the Ilikai parking garage. When Fargo kidnapped Agent Dupre, McGarrett went after them at a dock at the site of ruins of World War II structures near HNL. After sending Fargo and the fake bills into the water, McGarrett rescued Agent Dupre, who seemed genuinely relieved that he was there. Something tells me Marj Dusay was not comfortable being closed in the hold of the Alika.
Back to Kewalo Basin. Fisherman's Wharf was an immensely popular seafood restaurant at the Basin. It opened just after World War II ended. So popular was it that Governor John Burns had them cater a dinner he held for President Lyndon Johnson when he visited the Islands. It closed in about 2007 and was demolished in 2014. To drivers by, it was known for the blue swordfish that was perched atop the roof between the restaurant and the cocktail bar.