Haw. Rev. Stat. § 432D-31: Extension of dependent coverage.

Each individual or group policy, contract, plan, or agreement and each health maintenance organization offering individual or group policies, contracts, plans, or agreements that provides dependent coverage of children shall continue to make that coverage available for an adult child until the child turns twenty-six years of age. Nothing in this section shall require a policy, contract, plan, or agreement to make coverage available for a child of a child receiving dependent coverage.