Since there is no physical guichet, you can purchase tickets via:
Using the SNCF Connect website or the TER Grand Est portal . The Role of the Rural Train Station (Essay) Ouverture Guichet Gare Longuyon
The does not currently have an active ticket window (guichet) with a physical staff member for ticket sales. Instead, passengers are served by automatic ticket machines and the station remains open daily as a waiting area. Station Access and Opening Hours Since there is no physical guichet, you can
Located within the station for TER Grand Est tickets. Since there is no physical guichet
The station building (waiting room) is accessible every day, including public holidays: 05:30 to 20:30. Ticket Services