GSS International was founded by Kostantis Stratos in 2000 and since then became a member of the Hellenic Association of Travel Agencies (HATTA).

In 2006 the company licensed officially by IATA, thus improving customer service with speed and directness.

The quality and dynamism of the company certified through the customers satisfaction and integration, based on an assessment of the ICAP, the "Strongest Companies in Greece", but rather on the quality management certificate ISO 9001:

2008 which has, by TUV Austria Hellas No .: 0106035

In 2014 in the context of sustainable development GSS International started its cooperation with Lufthansa, under the umbrella of which serves as Lufthansa City Center Business Travel.

GSS International is a member of HAPCO (Hellenic Association of Professional Congress Organizers) and EFAPCO (European Federation of Associations of Professional Congress Organizers)