The 2026 season marked Toyota's entry into the Supercars Championship, the first time three manufacturers were represented simultaneously since Nissan's departure in 2019. Walkinshaw TWG Racing, formerly Walkinshaw Andretti United, became Toyota's factory team by switching from Ford Mustangs to the Toyota GR Supra in collaboration with Toyota Gazoo Racing; the team also changed its name after United Autosports sold their stake and Andretti Global was absorbed by TWG Motorsports in 2023. Brad Jones Racing also converted from Chevrolet Camaros to GR Supras, bringing the Toyota total to five cars.
Triple Eight Race Engineering reversed its long-standing General Motors allegiance, returning to Ford and the Mustang for the first time since 2009. The team became Ford's homologation team and expanded to a three-car operation for the first time since 2018, taking on a Teams Racing Charter from SCT Motorsport. Team 18 assumed the Chevrolet homologation role as a result of Triple Eight's switch, becoming the brand's third homologation team in the V8 Supercars era.
Several established competitors stepped back from full-time competition. Nick Percat retired from full-time racing and joined Triple Eight as a co-driver; his seat at Matt Stone Racing was taken by 2024 Super2 Champion Zach Bates. James Courtney also retired from full-time competition, joining Team 18 as a co-driver. Will Davison stepped back from Dick Johnson Racing, replaced by 2025 Super2 Series champion Rylan Gray, with Davison joining Grove Racing for enduro events.
James Golding moved to Blanchard Racing Team, departing PremiAir Racing. PremiAir fielded a new lineup: Declan Fraser returned to full-time competition for the first time since 2023, and Jayden Ojeda made his full-time debut after several wildcard and co-driver appearances since 2020. Jack Le Brocq left Erebus Motorsport to return to Matt Stone Racing, with Jobe Stewart graduating from Super2 to fill the Erebus seat.
The Euromarque Motorsport Park in Christchurch hosted its first Supercars event, the Christchurch Super 440, marking the first time the category ran two New Zealand rounds in a single season. The Bend 500 used the West layout rather than the International circuit layout for the first time since 2020, with the change intended to increase overtaking opportunities and improve spectator sightlines. Round 10, originally scheduled for Taupo, was relocated to Christchurch in response to incoming Cyclone Vaianu.
Points were awarded per race to any driver or car completing at least 75 percent of the race distance and still running at the finish. A result required at least 50 percent of the planned distance to be completed before championship points were allocated. Race distances and formats varied by round type, from 100 km sprint races at events such as the Sydney 500 to 250 km races at the Gold Coast 500 and the Sandown 500.