Williams currently uses Mercedes PUs but has the option to switch to another partner when the new regulations come in.
In theory, Mercedes might be obliged to part company with one of its three customers as under the 2026 PU regulations a manufacturer can only supply three teams, including its own works outfit, “unless agreed otherwise by the FIA.”
Ferrari will lose Sauber to Audi in 2026 and thus an extra supply will be available from Maranello.
Renault is known to be looking for customers and is set to be the partner of the Andretti team should it get an entry, but even if that happens Viry could also supply a third team.
The most intriguing option remains Honda. The Japanese company has declared its interest in participating in 2026, but with Red Bull developing its own Ford-backed PU for both of its teams, Honda now has to look for a new partner.
McLaren and Williams are obvious candidates, although clearly there are political problems to be addressed regarding a reunion with the former given the Woking team’s acrimonious split with Honda at the end of 2017.
Williams meanwhile will have to show signs of a potential long-term improvement in form in order to attract Honda.
“We are at the moment still in the process of making sure we understand all the options available to this team,” said Vowles.
“The rules contain some lines which state that theoretically as taken in 2025 this is the number of teams a PU manufacturer can supply. Same rules, by the way, that should have limited [Mercedes] this year down to less PU supplies than they currently have.
“I think that's an ongoing discussion. But no, we're not locked into Mercedes. And we're still in the process of reviewing.
“But we have to, as all teams will do as well, come to a decision fairly shortly. I think end of the year would be late. So a little bit before then."
Vowles downplayed the significance of his Mercedes connections: “As you would imagine, it would be foolish to simply just go with where I'm comfortable and what I know.
“If you're going to get your house painted, you get three quotes, I would highly recommend you do that if you don't. And it's the same here, I want to make sure I understand what's available to us."
