Abstract: Self service hotel operation system, comprising an internal system (10) having subsystems for carrying out different tasks including an internal PMS subsystem (14) a connection to an outer PMS subsystem (28) that service reservations and bookings, a HK subsystem (12) that carries out internal services and house cleaning tasks, a lock server (22) adjusting and controlling locks in the respective rooms, and a climate server (23) controlling the air condition means in the rooms, and a functional communication is provided between the internal system (10) and one or more travel organizers (24, 25) to perform operations connected with reservations, wherein the internal system (10) comprises an internal centre (10a) for interconnecting and coordinating the operations of said subsystems and comprises a wireless platform (11) to which any guest that wishes to use the hotel can obtain connection after downloading an application program in his/her own smart mobile device (29) and registration and entering into the syste