In 1805, the 3rd Dragoon Regiment was reorganized along with the rest of the army, and was placed under I Corp. In the same year, they would participate in the Battle of Austerlitz, another victory. In 1806, they were put under the 6th Cavalry Reserve Corp, clashing against Prussian forces at Jena, then against Russian forces at Elyau, and again at Friedland, before joining an observation Corp.