The Osean Maritime Defense Force[1] (OMDF) is the naval branch of the Osean Defense Forces. Osean ships serving under the OMDF carry the prefix OFS (Osean Federation Ship).[2]

The OMDF is one of the largest naval forces in the world and its fleets have an impressive battle record. The 3rd Osean Naval Fleet in particular participated in major conflicts at the turn of the 21st century.

The player is tasked with defending or serving the OMDF during the events of Ace Combat 5: The Unsung War, Ace Combat Zero: The Belkan War, and Ace Combat 7: Skies Unknown.


The OMDF was formed sometime by the 16th century, when Admiral Stafford formed the 3rd Osean Naval Fleet. Stafford subsequently earned the nickname "Father of the Navy".[3]

By July 1991, Osea had six Hubert-class aircraft carriers across its fleets. The OMDF issued a contract on July 29 to the Newport Sargo Shipyard for the construction of a seventh Hubert-class carrier, the OFS Kestrel.[2]

Belkan War

Early in the Belkan War, Osea initiated Offensive Campaign No. 4101 to capture the Futuro Canal and secure a sea route for advancing further north into Ustio and Belka. The OMDF's 3rd Osean Naval Fleet took part in this operation and used the opportunity to give the OFS Kestrel a trial voyage. Ustio mercenary pilots, including Galm Team, assisted the fleet's advance by wiping out Belkan resistance. With the operation's success, the OMDF was able to perform naval transit from Osea into Belka for the rest of the war.[4]

Circum-Pacific War

Main article: Circum-Pacific War

All right, gentlemen, it's time to clean house!
This article or section may require a cleanup to meet Acepedia's quality standards.

Fifteen years after Operation Costner, the Kestrel was again thrust into war when the Yuktobanian Air Force and Yuktobanian Navy launched a raid on Port St. Hewlett, an Osean naval base, both by air and sea. The Wardog Squadron was sent to defend the Kestrel at any cost. However, a rendevous in the Eglin Straits where the 3rd Osean Naval Fleet was supposed to regroup for a counterattack ended in disaster when ballistic missiles from the super-submarine Scinfaxi  sunk the carriers OFS Buzzard and OFS Vulture along with many escort vessels, Later in the war, the OMDF's LCACs shipped a tank battalion from the Osean Army to the Bastok Peninsula in Yuktobania, where they executed Operation Footprint, establishing a front-line base in Yuktobania. After this, the OMDF was likely responsible for safely moving Osean forces from Osea to Yuktobania.

On or around December 7, 2010, the Kestrel, as well as a number of other ships, probably from the 3rd Osean Naval Fleet, left the OMDF and formed the Kestrel Fleet. The Kestrel Fleet believed that the Belkan Gray Men was the true enemy, not Yuktobania. The Kestrel carried a squadron of four black fighters, Ghosts of Razgriz, who were launched on various missions against the Gray Men.

On December 29, 2010 during Operation Glory Horn, the Osean fleet led by the OFS Barbet , another OMDF aircraft carrier and the Kestrel's sister ship, is detected during an engagement between the Admiral Tsanev fleet and the Kestrel Fleet. Since the Kestrel Fleet had been working with three defecting Yuktobanian naval ships and under command of President Vincent Harling, the Osean fleet went rogue and attack the Kestrel Fleet. However, all rogue forces were completely decimated. The following day, on December 30, 2010, the Kestrel was attacked by an enemy submarine and was sunk, however, the Razgriz and most of its crew was able to escape, and the enemy submarine was destroyed.

By the end of the Circum-Pacific War, the OMDF was depleted, having lost much of its carrier force.

Lighthouse War

Main article: Lighthouse War

We've still got some work for you, too, so don't slack off now.
This article or section is a stub. You can help by expanding it.

Around ten years after the Circum-Pacific War, the OMDF, having rebuilt their strength after the war, found itself engaged with the Kingdom of Erusea's forces for control of the Lighthouse Space Elevator.




The OFS prefix is excluded since all ships listed here implicitly carry it. Vessels that have been sunk are denoted by the † symbol.



  1. File:3rd Osean Naval Fleet Emblem.png.
  2. 2.0 2.1 PS2/エースコンバット5 | BACKGROUND | 設定資料. Retrieved February 28, 2015.
  3. Commander, Third Fleet. Retrieved on 5 October 2017.
  4. Juggernaut, Ace Combat Zero: The Belkan War.