Aquatic Terrain Armored Transport

The AT-AT swimmer was manufactured in a joint venture between Kuat Drive Yards and Hydrospeare Corporation, and was derived from extreme modifications to the standard AT-AT that had been executed by the Imperial Army garrison on Kabaira.

The command deck was attached to a broad area of the ship which contained passengers. It operated in deep sea operations alongside TIE fighter boats and aquatic assault stormtroopers and could be found in Imperial aquatic military bases. The AT-AT swimmer could also be deployed by the Y-85 Titan dropship. It could carry 40 troops, and its cargo capacity was 600 kilograms.

Its shell-like armor was designed to withstand and protect the vehicle from the crushing pressures of deep water, the effects of salt and water, and blaster fire. Its head was capable of providing firing arcs in all directions.

The AT-AT swimmer had two modified heavy laser cannons, much like its land counterpart. Its main body was broader than that of the AT-AT to accommodate the four additional repulsorlift engines that keep it afloat. These four repulsorlift engines produced a powerful field strong enough to repel any object on the craft's ventral section, but it could be penetrated by strong swimmers where it was non-existent.

By 137 ABY, the design was heavily modified. The version used by Darth Krayt's Galactic Empire could operate underwater and had shields. It included at least 6 laser cannons, including a rear double laser cannon to stem attacks from the rear, and was fitted with a launch bay containing at least five Shark underwater fighters. The new design looked similar to the old one, although sleeker in design. The command bridge was also replaced by another similar to a standard AT-AT's command bridge. Additionally, these vehicles were known to have transported Sith Lords on several occasions.

The basis for the eventual Aquatic Terrain Armored Transport was created via the AT-AT Swimmer, which had been extreme modifications to the mech that were ordered by the Imperial Army garrison on Kabaira. This eventually ended up mass-produced, with some eventually being placed on Kaal, which proved enough of a problem to the Rebel's efforts on the planet that General Carlist Rieekan made a note while reviewing the official field manual for the Imperial Military, Imperial Handbook: A Commander's Guide, that they will need to import attack subs from Mon Calamari.

Over a century later, at least one updated AT-AT Swimmer was employed during the Genocide of Mon Calamari on Dac in 137 ABY, where it was used to transport Darth Azard and Sith scientist Vul Isen to the Soheras Trench. Isen had created a Sea Leviathan there, and the two used the Force to awaken it and command it to slaughter the Mon Calamari prisoners of Imperial Extermination Camp 28, and later search out and destroy every Mon Calamari in its path.

• Imperial Sourcebook
• Galaxy Guide 9: Fragments from the Rim
• Dark Empire Sourcebook
• Imperial Sourcebook, Second Edition
• Alliance Intelligence Reports
• "Imperial Garrisons" — Star Wars Adventure Journal 12
• Rules of Engagement: The Rebel SpecForce Handbook
• "Ask the Master" — Star Wars Insider 81
• "Blaster" — Star Wars Insider 107
• Star Wars: Imperial Handbook: A Commander's Guide