The Finn contributed to multiple constructors’ titles at Mercedes as Lewis Hamilton‘s teammate before he was replaced by George Russell.
Bottas, also 35, lost his Sauber drive after 2024 and rejoined Mercedes as its reserve driver for this year.
“From the moment I began speaking with Cadillac, I felt something different – something ambitious but also grounded,” said Bottas. “This isn’t just a racing project; it’s a long-term vision. It’s not every day that you get a chance to be part of something being built from the ground up and helping shape it into something that truly belongs on the F1 grid.
“I’ve had the honor of working with some of the best teams in the world, and I can already see the same professionalism and hunger here.”
Cadillac’s arrival marks the first brand-new F1 entry since Haas joined the grid in 2016. It also means there will be 22 cars on the grid since 2014.
Former Virgin and Marussia boss Graeme Lowdon has been appointed as Cadillac’s first Formula 1 team boss.
Although General Motors’ in-house Formula 1 power unit is scheduled for introduction later in the decade, Cadillac will initially enter using Ferrari customer engines.
Cadillac’s 2026 campaign will begin at a time of significant regulatory change in F1, with the introduction of next-generation hybrid power units and an increased emphasis on sustainability.