The Grove outfit scored just a point every three races over the course of the 2018 season, finishing the campaign with seven points.
They have a brand new driver line-up, as both Robert Kubica and George Russell come into the squad.
“Next year – is a new start for Williams and I spent a lot of time with Robert over the course of the year,” Williams said.
“I really enjoy his company, just his fighting spirit. We need that in this team at the moment.
“We need everybody pushing, and I think Robert is going to be a great addition for us for 2019 and beyond.”
Kubica will complete his own comeback to the sport, having suffered a life-changing rally crash back in 2010.
The Pole has not raced in the top tier of single-seaters since then, and will return after nine years away from F1.
“One of the things that impress me most about Robert is the fact that he didn’t get in the race seat for this year, yet he still took on the role of the reserve driver,” Williams continued.
“That shows a lot about his personality.
“He knows everybody in the team, he gets on well with everybody in the team, he’s dedicated, he spends a lot of time back in the factory in order to help us drive our performance.”