Developed under James Allison — who had joined Mercedes from Ferrari in 2016 — the W08 was designed at Brackley and powered by the Mercedes-Benz AMG F1 M08 EQ Power+ unit. The name "EQ Power+" was introduced to increase exposure of Mercedes' electric road car brand, while the AMG designation reflected the team's corporate relationship with Mercedes-AMG.
Key design changes included a revised front suspension geometry, with the upper wishbone attached to an extension before connecting to the upright, lifting airflow away from the sidepods. A T-wing aerodynamic device on the engine cover generated rear downforce; the bowl-shaped rear wing design carried over from the W07.
In-season upgrades were extensive. A major aerodynamic package at the Spanish Grand Prix redesigned the nose, bargeboards, and rear wing. Asymmetric brake setups were trialled in Azerbaijan. A comprehensive bargeboard revision arrived for Malaysia, addressing aerodynamic weaknesses. The 2017 W08 cars completed 5,102 kilometres across eight days of pre-season testing. In-season testing was conducted by George Russell, the 2017 GP3 Series champion.
The season opened with Sebastian Vettel winning in Australia after Hamilton exited the pits behind Max Verstappen following his pit stop. Ferrari mounted a serious title challenge through the first half of the year, winning races in Bahrain, Monaco, Canada, and Malaysia. At Monaco, both Mercedes drivers qualified outside the top two and Hamilton recovered to seventh.
Hamilton's title bid accelerated after Singapore. Ferrari's start crash — eliminating Vettel, Kimi Räikkönen, and Verstappen simultaneously — gifted Hamilton a lead he never surrendered through the final rounds. Hamilton won the Japanese Grand Prix to stretch his lead, and Mercedes clinched the Constructors' Championship in the United States. Hamilton secured his fourth Drivers' Championship at the Mexican Grand Prix, finishing ninth after first-lap contact with Vettel.
Bottas contributed significantly in his debut season with the team, winning in Russia, Austria, and Abu Dhabi. His three victories made him the highest-scoring rookie Mercedes driver since the team's works return in 2010.
Individual milestones accumulated through the year. Hamilton scored his sixty-fifth career pole at Canada, matching Ayrton Senna's second-place record. He surpassed Michael Schumacher's all-time pole record with his sixty-ninth at Monza. The British Grand Prix win was his fifth at Silverstone, matching Jim Clark and Alain Prost. His fiftieth career win in the United States tied him with Prost.
Unlike its predecessors, the W08 faced a genuine mid-season challenge from Ferrari, particularly through the power-sensitive circuits of Monaco, Canada, and Singapore. The car suffered from poor race starts at several rounds — attributed to a hardware issue with clutch warming — and from recurring power unit failures including Hamilton's retirement from the lead in Malaysia. The team's 668 constructor's points was their lowest total since the hybrid era began in 2014, and for the first time the two Mercedes drivers did not finish the season first and second in the championship, with Bottas third behind Vettel.
The W08 established Valtteri Bottas as a reliable and occasionally outstanding number-two driver, a role he would maintain until 2021. For Hamilton, the fourth championship drew him level with Alain Prost and left him one title behind Schumacher's seven. The car proved that while Mercedes could be pressured across a full season, the team's technical foundation remained robust enough to prevail even when rivals identified genuine competitive windows. On 10 December 2019, nine-time MotoGP champion Valentino Rossi drove the W08, repainted in W10 livery, at the Ricardo Tormo circuit.