The MSA-0011[Ext] Ex-S Gundam (aka Extraordinary-Superior Gundam) is an upgraded version of the MSA-0011 S Gundam that appears in Gundam Sentinel. It is piloted by Ryou Roots.

By adding several new armor, weapons, and engine modules the engineers of Task Force Alpha's Pegasus III were able to upgrade the MSA-0011 S Gundam into the Ex-S Gundam. The Ex-S Gundam still had three cockpits, but Ryou Roots was the only person who piloted the mobile suit, and due to Ryou's poor piloting skills, it was up to ALICE, the Ex-S Gundam's highly advanced artificial intelligence combat computer, to do most of the fighting against more skilled opponents.

With ALICE functioning as the co-pilot of the Ex-S Gundam, "she" was constantly getting more advanced. ALICE was constantly growing in comprehension and depth, and was swiftly evolving into something more akin to a fully rationalizing and thinking creature than a simple machine. ALICE could take full control of the Ex-S Gundam and its various components and weapons at any time, and would begin to do so constantly at times when "she" felt the Ex-S or Ryou were threatened. ALICE proved to be a useful co-pilot of the Ex-S Gundam, and was more than capable of compensating for Ryou's lack of skill.

For defensive purposes, the Ex-S Gundam featured additional armor on the front of the chest which afforded extra protection for the first two cockpits. This extra chest armor also featured an I-Field generator which created an invisible barrier of Minovsky Particles around the Ex-S Gundam's cockpit block, protecting it from ranged beam attacks. Additional armor added onto the front of the torso also protected the third cockpit, while extra armor on both sides of the legs featured more verniers, additional propellant tanks, and thrusters.

Two new large thruster units were mounted on the Ex-S Gundam's back, giving it incredible thrust and speed. Two large caliber beam cannons were mounted on both thruster units, giving the Ex-S Gundam two more back beam cannons than the S Gundam. The Ex-S Gundam's beam smart rifle was now attached to the front torso of the mobile suit instead of the hips, making room for the two hip beam cannons that were optional on the S Gundam to be attached to the sides of the Ex-S Gundam's waist permanently. The Ex-S Gundam's head featured four 60mm vulcan guns, while four additional 60mm vulcans were mounted on the tail stabilizer attached to the back.

The Ex-S Gundam also had remote weaponry in the form of an INCOM, a small wire-guided red disc stored in the Ex-S Gundam's forehead that could fire beams when deployed. The Ex-S Gundam also featured two reflector INCOMs, stored in the large knee armor, which could be deployed and guided by wire like a standard INCOM. Reflector INCOMs do not fire beams but instead reflect beam fired from the Ex-S Gundam or another unit, and redirect it in another direction. Lastly, for use in melee combat situations, the Ex-S Gundam featured two beam sabers, also stored in the knee armor.

Like its predecessor, the Ex-S Gundam was also capable of transforming into a waverider mode of sorts, but unlike the S Gundam, which divided into three separate components, the Ex-S Gundam changes into one large unit called the G-Cruiser. For its size, the G-Cruiser was incredibly fast and used for travelling over a great distance in a short amount of time. To conserve the fuel of the Ex-S Gundam for use in combat situations, the G-Cruiser had two large propellant tanks mounted in the front over the Ex-S Gundam's shoulders. These extra fuel tanks would be jettisoned when the G-Cruiser reaches the battlefield and transforms into the Ex-S Gundam.