The transformation of 1979 fundamentally redefined Spa-Francorchamps. The original circuit, established in the early 1920s using public roads among Stavelot, Malmedy, and Francorchamps, spanned 14.120 km and was one of the fastest and most dangerous circuits in the world. Drivers including Jackie Stewart described it as "ferocious as a tiger." Multiple fatal accidents and repeated driver boycotts — most notably the 1969 Belgian Grand Prix which was cancelled outright after drivers refused to compete — forced authorities to recognise the old layout's limits.
The new permanent circuit retained the Raidillon de l'Eau Rouge, Blanchimont, and the La Source hairpin — the final section of the old triangle where the new circuit rejoins the historic route — while eliminating the Masta Kink, the Malmedy chicane, the Stavelot hairpin bypass, and the long forest straights that had produced average speeds approaching 240 km/h (150 mph) in the final years of the old layout. The result was a shorter, safer 6.947 km circuit that opened for Formula One in 1983 after a period of further negotiation.
The combination of La Source hairpin, the Eau Rouge creek crossing, and the blind uphill Raidillon became the defining feature of the post-1979 circuit and arguably the most famous sequence in motor racing. Cars launch from the La Source hairpin onto a downhill approach, cross a stream at the bottom of a valley, then sweep uphill through a blind compression that peaks at a crest with no visible exit from the cockpit. Formula One cars handle the section at over 300 km/h (190 mph) due to downforce loads, while touring cars typically transit it at 160 to 180 km/h (99 to 112 mph).
Several major accidents have occurred at this section. Stefan Bellof died in a Porsche sportscar accident at Eau Rouge. Alex Zanardi suffered a serious crash there during the 1993 Belgian Grand Prix practice. In 1999, Jacques Villeneuve and teammate Ricardo Zonta both crashed at the Raidillon during qualifying. The death of Formula 2 driver Anthoine Hubert in 2019, which occurred on the Kemmel straight immediately after Raidillon, triggered the most significant post-1979 safety renovation, completed in time for the 2022 season.
The start/finish line was moved from the downhill straight before Eau Rouge (its original position) to the straight before La Source in 1981. A 2007 renovation, costing approximately 19 million euros with Wallonian government backing, moved the Bus Stop chicane closer to Blanchimont and shifted La Source forward, creating a longer pit straight. Prior to this renovation, the organiser had gone bankrupt, causing Spa to be dropped from the 2006 Formula One calendar.
Following the 2019 Hubert fatality and several other serious accidents at Raidillon, an 80 million euro safety and facilities upgrade was announced and completed by March 2022. Gravel traps were added at La Source, Raidillon de l'Eau Rouge, Blanchimont, Les Combes, and Stavelot. Run-off areas were expanded, and the circuit was slightly shortened to 6.985 km as the Jacky Ickx corner was bypassed in favour of a shorter, more protected section, enabling the track to accommodate FIM motorcycle World Championship events.
The lap record for the current circuit configuration is 1:44.701, set by Sergio Perez in a Red Bull Racing RB20 during the 2024 Belgian Grand Prix. The unofficial all-time quickest circuit time stood at 1:40.510, set by Oscar Piastri in a McLaren MCL39 during sprint qualifying at the 2025 Belgian Grand Prix.
Turn 11, a fast right-hander in the sector between Raidillon and the Bus Stop chicane, was renamed the Jacky Ickx corner from the 2018 Belgian Grand Prix onward, honouring the Belgian driver's career. Ayrton Senna's name is associated with the circuit through the occasion in 1992 when he stopped his racing car and ran to the aid of Erikk Comas, who had crashed heavily at Blanchimont during Friday practice, while other cars passed at racing speed.
Spa hosts the Formula One Belgian Grand Prix as its headline event, with the circuit contracted through to 2025 and beyond. The 24 Hours of Spa for GT cars is the circuit's other flagship, alongside the World Endurance Championship's 6 Hours of Spa-Francorchamps. The FIM Endurance World Championship runs an 8 Hours of Spa Motos round following the 2022 safety modifications. The circuit also hosts rounds of the FIA Formula 2 Championship, FIA Formula 3 Championship, GT World Challenge Europe, and the Intercontinental GT Challenge, along with the 25 Hours of Spa for Uniroyal Fun Cup cars — one of the longest motor races in the world by duration.
The Ardennes weather creates conditions unique among major circuits. Heavy rain at one point of the track while another sector remains dry is commonplace, and this pattern has produced some of the most controversial and dramatic Formula One races on record, including the 1998 Belgian Grand Prix, which saw a 14-car pile-up on the opening lap.