The 1983 season ran in close partnership with the 1983 European Endurance Championship, sharing five of its seven race events held in Europe before the calendar moved to international venues. This overlap meant that many drivers and teams competed in both championships simultaneously, raising the competitive intensity at the shared rounds. All events covered 1,000 kilometres with the sole exception of the 24 Hours of Le Mans.
The championship encompassed multiple parallel titles: the outright World Endurance Championship for Drivers (open primarily to Group C cars), the World Endurance Championship for Makes (Group C only), the Group C Junior Cup for smaller-displacement prototypes, and the Grand Touring Cup for Group B machines.
To score points, a team was required to complete 90 percent of the race winner's distance. Drivers were required to complete at least 30 percent of their car's total race distance to qualify for championship points. Group C Junior and Group B competitors earned additional championship points for any finish within the overall top ten outright positions, providing an incentive for smaller-class entries to punch above their category.
For the Makes Championship, only the best result from each manufacturer counted at any given round, and only the five best results from the entire season were retained toward each manufacturer's final tally. The FIA identified a manufacturer as the combination of engine builder and chassis builder; where these differed, the engine constructor took precedence in the official naming.
Jacky Ickx successfully defended his Drivers title, continuing the dominant partnership between Ickx and Porsche that had defined the early Group C era. Porsche's Group C machines proved consistently superior across the international rounds, and the German manufacturer secured the Makes Championship with a comfortable margin.
The Group C Junior Cup was a separate competition for smaller-engine prototypes, and Giannini Alba claimed that title, reflecting the depth of competition in the lower-displacement classes that the championship structure encouraged. Porsche also dominated the Grand Touring Cup for Group B cars.
The Monza round carried a notable administrative detail: an Italian Championship Group 6 race ran concurrently, though those cars completed only 14 laps and did not cover the full endurance distance, meaning they were treated as a separate event.
The 1983 season consolidated the Group C era that had been established the year before. The dual-championship structure — sharing rounds with the European Endurance Championship — expanded the audience and grid for European rounds, while the international legs at circuits outside Europe gave the series a genuine world championship character. Porsche's back-to-back dominance with Ickx at the wheel confirmed the 956 as the era's definitive Group C car and laid the groundwork for an extended period of Porsche dominance that would persist through the mid-1980s.