Judgment of the Court (Fifth Chamber) of 15 April 2021.#SK Telecom Co. Ltd. v Finanzamt Graz-Stadt.#Request for a preliminary ruling from the Bundesfinanzgericht, Außenstelle Graz.#Reference for a preliminary ruling – Value added tax (VAT) – Directive 2006/112/EC – Determination of the place of supply of telecommunications services – Roaming of third-country nationals on mobile communications networks within the European Union – Point (b) of the first paragraph of Article 59a – Option for Member States to transfer the place of supply of telecommunications services to their territory.#Case C-593/19.