45 C.F.R. § 156.155
Enrollment in catastrophic plans
(a) General rule. A health plan is a catastrophic plan if it meets the following conditions:
(1) Meets all applicable requirements for health insurance coverage in the individual market (including but not limited to those requirements described in parts 147 and 148 of this subchapter), and is offered only in the individual market.
(2) Does not provide a bronze, silver, gold, or platinum level of coverage described in section 1302(d) of the Affordable Care Act.
(3) Provides coverage of the essential health benefits under section 1302(b) of the Affordable Care Act, except that the plan provides no benefits for any plan year (except as provided in paragraphs (a)(4), (b), and (c) of this section) until the annual limitation on cost sharing in section 1302(c)(1) of the Affordable Care Act is reached.
(4) Provides coverage for at least three primary care visits per year before reaching the deductible.
(5) Covers only individuals who meet either of the following conditions:
(i) Have not attained the age of 30 prior to the first day of the plan or policy year.
(ii) Have received a certificate of exemption for the reasons identified in section 1302(e)(2)(B)(i) or (ii) of the Affordable Care Act.
(b) Coverage of preventive health services. A catastrophic plan may not impose any cost-sharing requirements (such as a copayment, coinsurance, or deductible) for preventive services, in accordance with section 2713 of the Public Health Service Act.
(c) Coverage to prevent surprise medical bills. A catastrophic plan must provide benefits as required under sections 2799A-1 and 2799A-2 of the Public Health Service Act and their implementing regulations in §§ 149.110, 149.120, and 149.130 or any applicable State law providing similar protections to individuals, and will not violate paragraph (a)(3) of this section solely because of the provision of such benefits before the annual limitation on cost sharing is reached.
(d) Application for family coverage. For other than self-only coverage, each individual enrolled must meet the requirements of paragraph (a)(5) of this section.