The captain and first deputy of a large inland waterway or seagoing vessel flying the Hungarian flag engaged in international traffic must be EEA nationals.
"§ 34. [...]
(3) The master and first deputy of a large inland waterway or seagoing vessel flying the Hungarian flag engaged in international traffic may be a national of a Member State of the European Economic Area.[...]" (Law on the management of water transport (XLII of 2000), last amended 1 July 2021, § 34 [google translation])
Law on the management of water transport (XLII of 2000), last amended 1 July 2021, § 34
[<a href="https://njt.hu/jogszabaly/2000-42-00-00">Law</a>]