By the late 1960s, it was clear that changes to the Series IIA were required if Land Rover was going to keep its edge. Hence in 1971, the Series IIA was replaced by the Series III. Cash was limited and market research showed that customers were not looking for radical changes. Hence the Series III was an evolution of the Series IIA design, rather a complete revamp.

The most significant change was the replacement of the gearbox with a completely new gearbox that incorporated synchromesh on all forward gears. The ratios were also revised, with lower Reverse and 1st gears. The Low Range ratio was also reduced. Clutch design was also modified to include a diaphragm spring, resulting in smoother and quieter gear changes. Brakes were also improved, and a heavy duty Salisbury rear axle was fitted as standard to all 6 cylinder vehicles. From 1972, the Salisbury became a standard fitment on all 109" vehicles. The electrical system was also upgraded with the dynamo replaced by an alternator.

The body remained virtually unchanged, although the metal grille was replaced with a plastic grille designed to match the new headlamp position introduced in 1968. Although there were few external changes, the Series III looked very different on the inside. The dash was redesigned with the addition of padding. The instrument panel was moved to be in front of the driver. The door interiors were upholstered, and a much-improved heater was fitted. There were even provisions for a radio!