Haw. Rev. Stat. § 572D-6: Enforcement.

(a) A premarital agreement is enforceable and shall be binding in any action unless the party against whom enforcement is sought proves that:

(1) That party did not execute the agreement voluntarily; or

(2) The agreement was unconscionable when it was executed and, before execution of the agreement, that party:

(A) Was not provided a fair and reasonable disclosure of the property or financial obligations of the other party;

(B) Did not voluntarily and expressly waive, in writing, any right to disclosure of the property or financial obligations of the other party beyond the disclosure provided; and

(C) Did not have, or reasonably could not have had, an adequate knowledge of the property or financial obligations of the other party.

(b) If a provision of a premarital agreement modifies or eliminates spousal support and that modification or elimination causes one party to the agreement to be eligible for support under a program of public assistance at the time of separation or marital dissolution, a court, notwithstanding the terms of the agreement, may require the other party to provide support to the extent necessary to avoid eligibility for public assistance.

(c) An issue of unconscionability of a premarital agreement shall be decided by the court as a matter of law.