Because of various sources of provisioning, the production of the walls of Panzer III was not uniform. The physical properties were roughly equal to the British anti-projectiles material but as a whole was not higher to it. The assembly was done either by riveting or by weldings (of which resistance was rather weak).

Additional armour-plate mounted with an interval.

src: Connaissance de l'Histoire (Hachette), n°17

This shielding although was improved progressively with the development was insufficient to maintain Panzer III in a role of battle tank because the thickness never exceeded the 50-57mm at the significant points. One tried well to correct this defect by adding additional plates of 20mm at the same places (frontal plate of the superstructure and shield). These plates were assembled with an interval in order to reduce the perforating capacity of the enemy projectiles. In the same order of idea on the model M, armoured skirts (Schürzen) of 5mm will be mounted on the sides of the hull and the circumference of the turret. Did not prevent Panzer III to see it retrogressed in second line in missions of supports for example.

To still improve protection, the antimagnetic paste (Zimmerit) will be applied to the oblique and vertical walls late models to prevent the installation of mines.

For more data on the thicknesses of the various walls for each model, to see the charts in the category "Production/Data"