5. Member States that do not share a land border with any other Member State may exempt from the application of paragraph 1 passenger ships performing transnational voyages under public service obligations or public service contracts to the ports of call of other Member States. No such exemptions shall apply beyond 31 December 2029. Prior to the entry into force of those exemptions, Member States shall notify them to the Commission. The Commission shall publish those exemptions in the Official Journal of the European Union.