The Adriatic - Ionian Initiative (ADRION) is one of the activities originated from the signature of the "Ancona Declaration" by the Foreign Ministers of Albania, Bosnia and Herzegovina, Croatia, Greece, Italy and Slovenia at the end of the Summit on Development and Security on the Adriatic and Ionian Seas, held in Ancona (Italy) in May 2000. As the Declaration states, strengthening regional cooperation helps to promote political and economic stability, thus creating a solid base for the process of European integration. From the very moment of its institution the goal of facilitating the enlargement of the EU in the Western Balkans was clear.

The Initiative was later extended to the Federative Union of Serbia and Montenegro, and after the referendum in Montenegro, both States preserved the status of Participating Countries.

This commitment had a concrete follow-up between Navies on the 1^st December 2004 when the delegates of Navies of Albania, Croatia, Greece, Italy, Montenegro and Slovenia met in Rome for the 1^st ADRION Seminar, which in fact launched the Initiative.

ADRION also includes a simulated computer assisted exercise (CAX) and training at sea (LIVEX). Both activities take place annually, organized on a rotating basis by one of the six ADRION Navies.

The first ADRION LIVEX took place in 2006.

During the 9^th edition of the Regional Seapower Symposium (RSS) in Venice, the first meeting of the Heads of Marines of the ADRION countries was held, during which the discussion was on the achievements and new ideas to give further impetus to the Initiative. In accordance with the findings of the meeting, two Technical Arrangements (TA) were agreed in the following ADRION Seminars: one for the establishment of an On Call Maritime Force (OCMF) and the other for Maritime Security, which were signed during the 10^th RSS in October 2015.

The following are the elements that characterize the two TAs:

1. OCMF
   
   The OCMF provides for the establishment of an "On Call" maritime force with periodic activation (mostly once a year), in order to improve integration between the ADRION Marines and ensure greater presence and surveillance in the Adriatic-Ionic basin. The OCMF will be able to carry out both exercises and real activities (presence and surveillance, humanitarian assistance, disaster relief, search and rescue). The OCM Does not provide for the establishment of a permanent structure and the OPCOM and OPCON of the forces will always remain with the individual nations. The OCMF will operate under an annual Force Commander, which will exercise TACOM, supported by a small multinational staff.
2. MS
   
   The TA on MS is aimed at increasing cooperation, the exchange of information between the operating rooms and optimizing the use of their respective structures in the Adriatic-Ionic area. This agreement also provides for an exchange of information on anti-pollution activities and encourages the opening up to the Marine ADRION of any training event conducted by the individual Marines involved in the initiative.

The leadership of Italian Navy, in collaboration with the Hellenic Navy, has enabled ADRION's 15 years of activity to fully achieve the main objective of contributing to the integration and interoperability of the Navies that face and have interests in the Adriatic-Ionian area.

With this in mind, ADRION acted as a push factor for the entry as new members of NATO of the participating countries, which ended in 2017 with the entry of Montenegro.

In addition, all participating Navies, with the exception of Albania and Montenegro, for which the accession process is still ongoing but in its final stages, are now part of the European Union.