12 Hours of Sebring

The Sebring circuit opened in 1950, blending former airport runways with narrow two-lane service roads. The first race was a six-hour event on New Year's Eve 1950. The inaugural 12 Hours of Sebring followed in March 1952. From 1953 to 1972 the race was a round of the FIA's premier sports car championship, contested under names including the World Sportscar Championship and the International Championship for Makes.

During the 1950s, Sebring was the most important American race for European factory teams. It was the only occasion in that decade when major European manufacturer squads and their drivers crossed the Atlantic in force. Among those who competed were Juan Manuel Fangio, Alberto Ascari, Nino Farina, Stirling Moss, and Mike Hawthorn. The 1957 race was the only American event that five-time world champion Fangio ever won. The Formula One United States Grand Prix did not exist until 1959, making Sebring the pre-eminent meeting point of American and European motorsport through that era.

The 1966 race marked a turning point in the event's history. Five people died during the race — more than in the previous 15 years combined. Bob McLean crashed approaching the hairpin; his car rolled, struck a utility pole, and exploded. In a separate incident Mario Andretti, driving a Ferrari, collided with a Porsche on the Warehouse Straight near the Webster Turns, killing four spectators before crashing into an adjacent warehouse.

The aftermath prompted a comprehensive overhaul of the circuit and its facilities. The Webster Turns were eliminated, the Green Park Chicane was inserted to move the straight away from the airport warehouses, and other safety measures were implemented. Since those changes, the circuit has seen only four fatalities — a remarkable safety record given the venue's age and character.

The track's unique heritage — airport taxiways and service roads laid on concrete — gives it an unmistakably rough surface that punishes suspension, tyres, and driver bodies across the 12 hours. The Florida heat adds a further reliability dimension. For teams preparing for Le Mans, Sebring functions as an ideal dress rehearsal because its technical demands — particularly on transmission, cooling, and tyre management — closely mirror those of the French circuit at a fraction of the race length.

Unlike circuits built for modern motorsport, much of the Sebring layout retains the character of its airfield origins: long straights interrupted by relatively tight corners, minimal run-off in places, and an atmosphere that blends the industrial with the exotic.

Races through 1969 began with the traditional Le Mans-style running start, in which drivers sprinted across the track to their cars. The format was abolished from 1970, the same year Jacky Ickx's walking protest against the Le Mans start at the 1969 French race prompted its wider retirement from endurance racing. Since 1970, Sebring has used rolling starts.

The race has passed through several sanctioning bodies and championship frameworks. For much of its history it counted toward the World Sportscar Championship and later the IMSA GT Championship and American Le Mans Series. From 2014 it became the second round of the IMSA WeatherTech SportsCar Championship, which later became the IMSA SportsCar Championship. In 2012 the race served as a one-off round of the FIA World Endurance Championship before returning to the ALMS for 2013.

Tom Kristensen holds the record for the most overall victories by a driver, with six wins: 1999, 2000, 2005, 2006, 2009, and 2012. The Audi R8 prototype achieved six overall victories, one fewer than the all-time record of seven held by the Porsche 935.

Notable results include the Audi R10 TDI diesel prototype winning its very first competitive outing at the 2006 race, and the 2005 debut of the Chevrolet Corvette C6.R and Aston Martin DBR9, with Aston Martin winning the GT1 class for the first time in 49 years.

The 1966 race also produced an unusual result when Dan Gurney, leading on the final lap in a Shelby American Ford GT40, had his engine seize near the end. He pushed his car across the finish line, which was ultimately deemed a rules violation, and he was not credited with the finish; Ken Miles and Lloyd Ruby were the winners.

In 2020 the pandemic caused the race to be rescheduled from its traditional March slot to November. That season also featured a shorter three-hour race held in July as part of the championship's restart, making it the only year Sebring hosted two events.