The Imperial Aquatic Garrison functioned as an IM-A-761 Oceanic Garrison for the Imperial forces. It was situated 200 kilometers to the southeast of Fitsay, found on the waterworld planet called Sedri.
The Aquatic Garrison of the Empire mirrored the design of an IM-A-761 Oceanic Garrison. Its architecture closely resembled a land-based IM-455 modular garrison, with the key distinction being that its lower level was submerged rather than built underground. An almost undetectable underwater energy fence protected the garrison, supplemented by probe droids and proximity mines deployed within the fenced area.
To keep it afloat, the base utilized a flotation collar. To counteract drifting and ensure overall stability, tractor beam projectors anchored the garrison to the sea floor. While the facility included doors that opened directly to the ocean for launching ships from a vehicle bay, underwater launch ports were also an option.
While the base's design was typical for water-bound planets, the garrison on Sedri was still in the process of being constructed. It was also understaffed because navigation to Sedri proved dangerous until the Golden Sun met its end. As a result, the base housed fewer than 250 personnel, a stark contrast to the intended 3,000. The Sedri garrison's inventory included 50 stormtroopers, 30 seatroopers, 15 waveskimmers, 3 wavespeeders, a single AT-AT Swimmer, 10 TIE Fighters, and a pair of TIE fighter boats, among other vehicles and personnel.
The Empire's interest in Sedri waned in the months following the Golden Sun's destruction, leading to the abandonment of the garrison. The lack of upkeep meant the garrison was projected to sink within a year.
Although the back cover of Battle for the Golden Sun refers to it as the Imperial Sea Garrison, it is more commonly known as the Imperial Aquatic Garrison.