They were different experiences for all three. Which one will Sainz emulate?
Alain Prost - McLaren 1984-89/Ferrari 1990-91
Prost had already started his F1 career with a season at McLaren in 1980 before rejoining the team in 1984 following three seasons with Renault.
It was at McLaren that Prost made his name, of course, winning on his debut with the team in Brazil, and although missing out on the title that season by half a point to Niki Lauda, the Frenchman was champion in 1985, '86 and '89. His infamous feud with then team-mate Ayrton Senna sparked his departure to Ferrari.
As in '89, with the duo now on opposing teams, they clashed again in the penultimate race in Japan, with Senna intentionally driving into Prost, so enabling him to win the title, and help McLaren claim the constructors' championship.
Prost's short spell with Ferrari ended in acrimony as his contract was terminated with a race remaining of the '91 season due to his public criticisms of an uncompetitive car in particular.
Gerhard Berger - McLaren 1990-'92/Ferrari 1993-'95
Berger's three years with McLaren were sandwiched by two three-season spells with Ferrari. A wretched 1989 campaign, in which he retired 12 times in the 15 races he competed that year in the Scuderia's unreliable 640 played a role in his departure to McLaren.
Despite high hopes as McLaren was the best team in F1 at that time, Berger was effectively wingman to Senna as he won only three grands prix in his three years with the team before accepting a lucrative offer to return to Ferrari.
Sadly, for the Austrian, they were difficult seasons as he scored only two wins in 49 starts, along with an additional 20 retirements. It was far from the return Berger had expected.
Kimi Raikkonen - McLaren 2002-'06/Ferrari 2007'-09
Without a doubt the most successful of the trio who have previously left McLaren to join Ferrari.
After five years with McLaren, Raikkonen departed after twice finishing as runner-up in the drivers' championship, in 2003 and again in '05, finishing two points adrift of Ferrari's Michael Schumacher and 21 behind Renault's Fernando Alonso respectively.
Ferrari used the Italian Grand Prix of 2006 to announce they had signed Raikkonen on a three-year contract, and he did not disappoint.
Raikkonen won on his debut in '07 and went on to win the title that year in the most dramatic of circumstances, pipping McLaren duo Lewis Hamilton and Alonso by a point, after the Briton, in particular, threw away a 17-point lead with two races remaining, both won by the Finn.
That proved to be the crowning glory of Raikkonen's three years with Ferrari - and of his career - as he has since failed to scale such heights, although he remains one of the most popular figures in the sport.
Carlos Sainz - McLaren 2019-'20/Ferrari 2021-?
It is a chapter yet to be written but the signs are promising for Sainz. Alongside Leclerc, they form Ferrari's youngest driver pairing for 50 years. The Scuderia has rolled the dice and taken a gamble. Now it remains to be seen whether it will pay off.
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