Mölders joined the "Preußisches Infanterieregiment Nr. 2", an infantry regiment under the command of "Oberst" Siegfried Haenicke and subordinated to the 1st Division of the Reichswehr in Allenstein, East Prussia on 1 April 1931, serving as an officer cadet in the infantry. He attained the rank of "Fahnenjunker"-"Gefreiter" on 1 October 1931, rising to "Fahnenjunker"-"Unteroffizier" on 1 April 1932. After completing his basic military training in October 1932, he transferred to the Military School Dresden. On 1 June 1933, he successfully completed his training in Dresden and was promoted to ensign. He again was transferred, this time to the 1st Prussian Pioneer Battalion (Infantry Regiment 2) at the Pioneer School in Munich. During his training years, Mölders made his first attempt to fulfil his dream of flying and volunteered for pilot training, but was declared unfit for flying. He tried again and was given conditional permission ("bedingt tauglich"—with constraints) to begin flight training.