The car was predominantly driven by Felipe Massa and Lance Stroll, who made his Formula One début with the team.
Williams started the season as the fourth quickest team ahead of arch rivals Force India.
At the Hungarian Grand Prix, Massa withdrew from the race weekend when he became ill after the third practice session on Saturday.
Williams confirmed reserve driver and Sky Sports F1 pundit Paul di Resta would replace Massa for the rest of the weekend.
Alcohol laws meant Williams could not use their red Martini stripes in Abu Dhabi, instead using a blue livery.