The Le Mans Prototype lineage had long been divided into two main classes: LMP1, which by the 2010s had evolved into a hybrid-powered top tier, and LMP2, a professional-grade open prototype class. While LMP2 remained highly competitive and well-attended, entry costs were significant enough to limit access for developing teams and drivers.
The ACO introduced LMP3 in 2015 to bridge the gap between GT4/GT3-style production-based racing and full prototype competition, offering a closed-cockpit prototype experience at substantially lower cost than LMP2. Capping chassis, engine, and upgrade kit prices was central to the concept, preventing development spending arms races that could otherwise undermine the accessibility objective.
First-generation LMP3 cars, eligible from 2015 to 2019, were powered by a 5.0-litre normally-aspirated Nissan VK50VE V8 engine producing 310 kW (420 hp). Approved chassis from this era included the Ginetta-Juno P3, Ligier JS P3, Norma M30, ADESS-03, and the Ave-Riley AR-2. Minimum weight was initially set at 900 kilograms, later increased to 930 kilograms after the powertrain package proved heavier than anticipated.
A revised second-generation LMP3 ruleset took effect in 2020, introducing new cars: the Ginetta G61-LT-P3, Ligier JS P320, Duqueine D-08, and an updated ADESS-03 Evo. Teams transitioning from first-generation cars could use an upgrade kit to bring existing chassis to the new specification. The second-generation cars used a 5.6-litre Nissan engine, increasing power to 340 kW (455 hp).
From 2025, a further update introduced twin-turbocharged 3.5-litre Toyota engines producing 350 kW (470 hp), with a corresponding weight limit increase to 1,000 kilograms to accommodate the new engine and cooling package. New cars entering service from 2025 include the Ginetta G61-LT-P3 Evo, Ligier JS P325, Duqueine D09, and the ADESS AD25.
LMP3 runs in several endurance racing series. In Europe, the European Le Mans Series (ELMS) is the primary championship host, and the class has also competed in the Michelin Le Mans Cup. Other series hosting LMP3 include the Asian Le Mans Series, the IMSA VP Racing SportsCar Challenge, and Prototype Cup Germany. Dedicated series such as the FRD LMP3 Series and the British LMP3 Cup have also been created specifically for the class.
ELMS team champions and runners-up in LMP3 receive automatic entries to the following year's 24 Hours of Le Mans in the LMP3 class, providing the category's top competitors with a direct pathway to the world's most famous endurance race.
LMP3 was expressly designed as the first rung on the ACO's prototype ladder. It serves the same purpose for prototype racing that Formula 4 or GT4 serves in their respective disciplines: a controlled-cost, technically demanding environment where drivers and team personnel can develop prototype-specific skills — aerodynamic sensitivity, tyre management over longer stints, pit stop discipline, traffic management — before stepping up to LMP2.
The closed-cockpit configuration distinguishes LMP3 from the open-cockpit LMP2 cars and connects it to the broader Le Mans Prototype philosophy, which from the 2020s moved definitively toward closed bodywork across all classes. The class specification prevents testing and development escalation by capping constructor licences and standardising the powertrain, ensuring competition is decided by driver skill and team execution rather than technical spending.
LMP3's introduction created a viable amateur and semi-professional prototype championship ecosystem that had not existed before 2015. The class attracted new teams and driver rosters into endurance prototype racing that previously lacked a suitable entry point, widening the participant base of the European, Asian, and North American endurance scenes. As of 2026, with the introduction of Toyota-powered third-generation machinery, LMP3 continues to evolve within its core mission: maximum accessibility to prototype competition at controlled cost, as a stepping stone toward the highest levels of endurance racing.