Haw. Rev. Stat. § 383-36
Notice of a determination or redetermination upon a claim shall be promptly given to the claimant, by delivery thereof or by mailing the notice to the claimant's last known address. In addition, notice of a determination or redetermination with respect to the first week of a benefit year shall be given to each employer by whom the claimant was employed during the claimant's base period, and to the last employing unit by whom the claimant was employed, and notice of any determination or redetermination which involves the application of section 383-30 shall be given to the last employing unit by whom the claimant was employed, in every case by delivery thereof to such party or by mailing the notice to the party's last known address.
HRS § 383-36