IMSA Calendar 2025

The IMSA WeatherTech SportsCar Championship stands as North America's premier sports car racing series, delivering a 2026 season of 11 race weekends that blend high-speed sprint competition with demanding endurance challenges. From the 24-hour marathon at Daytona International Speedway to street circuits in Long Beach and Detroit, the championship showcases multi-class racing across the United States and Canada.

What is IMSA?

The IMSA WeatherTech SportsCar Championship features four distinct classes competing simultaneously on track: Grand Touring Prototype (GTP), Le Mans Prototype 2 (LMP2), GT Daytona Pro (GTD Pro), and GT Daytona (GTD). This multi-class format creates a dynamic racing environment where different categories of cars share the same circuit, each pursuing separate championships while navigating traffic from faster and slower competitors.

Championship Structure

The series features separate points competitions for Drivers', Teams', and Manufacturers' Championships across all four classes. The GTP class represents the pinnacle, featuring hybrid-powered LMDh and LMH machinery from manufacturers including Porsche, Cadillac, BMW, Acura, and Aston Martin. The LMP2 class runs standardized 2017-specification prototypes powered by Gibson V8 engines. Both GT categories utilize GT3-specification cars from manufacturers worldwide, with GTD Pro fielding professional driver lineups and GTD featuring mixed amateur and professional combinations.

A centerpiece of the championship is the IMSA Michelin Endurance Cup, comprising five long-distance races where all four classes compete: the Rolex 24 at Daytona (24 hours), Mobil 1 Twelve Hours of Sebring (12 hours), Sahlen's Six Hours of The Glen, the Motul SportsCar Endurance Grand Prix at Road America (upgraded to six hours for 2026), and the Motul Petit Le Mans (10 hours). An additional sprint race at Indianapolis Motor Speedway rounds out the six events where all classes compete together.

Race Format and Calendar

The 2026 calendar balances endurance events with shorter sprint races. Sprint events at Long Beach and Detroit run 100 minutes, while races at Laguna Seca, Canadian Tire Motorsport Park, and Indianapolis extend to 2 hours and 40 minutes. The Michelin GT Challenge at Virginia International Raceway remains a GT-only event featuring only the GTD Pro and GTD classes.

Race weekends typically include practice sessions, qualifying, and the main event. Endurance race weekends span multiple days with extended on-track activity, driver briefings, and technical inspections. The season opens with the Roar Before The 24 test session in mid-January, followed immediately by the Rolex 24 at Daytona, establishing momentum that carries through to the season finale at Road Atlanta in early October.

Technical Regulations and Competition

IMSA applies Balance of Performance adjustments across all classes to ensure competitive racing regardless of manufacturer. The GTP class combines LMDh cars with controlled hybrid powertrains and LMH entries, maintaining compatibility with international endurance racing regulations including the 24 Hours of Le Mans. GT classes feature production-based sports cars modified to GT3 specifications, with manufacturers including Porsche, Ferrari, Lamborghini, Corvette, McLaren, and Ford fielding entries.

Why Fans Follow IMSA

The championship attracts top-level driving talent from multiple racing disciplines, including Formula 1, IndyCar, and international sports car racing. The multi-class format provides constant on-track action, with strategic elements like fuel management, tire strategy, and driver rotations adding layers of complexity to endurance events. The variety of circuits—from high-speed ovals and permanent road courses to challenging street circuits—ensures each race presents unique challenges for teams and compelling racing for spectators.