Carlos Sainz Vázquez de Castro (Spanish pronunciation: [ˈkaɾlos ˈsajnθ ˈβaθkeθ ðe ˈkastɾo] ^ⓘ; born 1 September 1994) is a Spanish racing driver who competes in Formula One for Williams. Sainz has won four Formula One Grands Prix across 12 seasons.

Born in Madrid, Sainz is the son of two-time World Rally Champion Carlos Sainz. Graduating from karting to junior formulae in 2010, Sainz won his first championship at the Formula Renault NEC in 2011 with Koiranen, finishing runner-up to Robin Frijns in the Eurocup that year. In 2012, Sainz contested British Formula 3, the Formula 3 Euro Series and FIA European Formula 3 with Carlin. Sainz progressed to the GP3 Series with Arden in 2013, finishing tenth in his rookie season. He then found success in the Formula Renault 3.5 Series, winning the championship in 2014 with DAMS.

A member of the Red Bull Junior Team since 2010, Sainz signed with Toro Rosso in 2015, debuting alongside Max Verstappen. He remained at Toro Rosso until the 2017 United States Grand Prix, where he replaced Jolyon Palmer at Renault, having already signed with the team from 2018 onwards. Sainz moved to McLaren in 2019, ending his association with Red Bull. He took his maiden podium at the Brazilian Grand Prix that year, followed by another at the Italian Grand Prix in 2020. Sainz signed for Ferrari in 2021, replacing Sebastian Vettel to partner Charles Leclerc. After a winless debut season for Ferrari, Sainz took his maiden pole position and win at the British Grand Prix in 2022. He took further wins for Ferrari at Singapore in 2023, as well as Australia and Mexico City in 2024. Replaced by Lewis Hamilton for 2025, Sainz joined Williams to partner Alexander Albon, claiming two podiums at the Azerbaijan Grand Prix and the Qatar Grand Prix.

As of the 2026 British Grand Prix, Sainz has achieved four race wins, six pole positions, four fastest laps and 29 podiums in Formula One. Sainz is contracted to remain at Williams until at least the end of the 2026 season.

Carlos Sainz Vázquez de Castro was born on 1 September 1994 in Madrid, Spain, to mother Reyes Vázquez de Castro and father Carlos Sainz. His father is a rally driver, who won the World Rally Championship twice in 1990 and 1992, with 26 rally victories. Sainz Jr. was mentored by his father throughout his journey to F1.

In 2016, Sainz was named Ambassador of María de Villota's Legacy, as he was coached by her at driving school in Madrid. He has spoken about how he was personally affected by her death in 2013, and he has kept a star on his helmet since 2014 in honor of her.

Sainz started his career in karting in 2006, after participating in smaller series, in 2008, he won the Asia-Pacific KF3 title, as well as finishing runner-up in the Spanish Championship. In 2009, he also won the Junior Monaco Kart Cup, and was runner-up in the European KF3 Championship. While at driving school in Madrid, he was coached by María de Villota.

Sainz raced in Formula BMW Europe in 2010 with the EuroInternational team. He was also part of the Red Bull Junior Team programme. He made his Formula BMW debut during a guest drive in the Formula BMW Pacific series at Sepang, Malaysia where he was ineligible to score points as a guest driver. However, he placed second in the opening race in Malaysia. That debut was followed by a fourth place. The following race day, he retired from the first race but won the second race. He finished seventh in the following race. He missed the next race in China but returned to Singapore. He finished sixth in the first race and second in the second race. He missed the Japanese races but returned to win the season finale in Macau. Overall, in nine races he achieved three pole positions, two wins, and two fastest laps.