Popular routes include Ala Moana Regional Park, the tracks around Magic Island Lagoon, the South King Street protected bike lane, trails by the Ala Wai Canal and the 4.3-mile Waikiki Loop. Keep in mind that Hawaii has a state law requiring cyclists under 16 to wear helmets. Also, be aware of traffic at all times; Honolulu is a busy and crowded …
https://www.lonelyplanet.com/articles/getting-around-honolulu