Valtteri Bottas was not able to win a Grand Prix with Williams in 77 races
Bottas, 27, competed for Williams in 77 races and finished on the podium nine times but never on the top step.
Williams have won nine Constructors' Championship titles in their 40-year history but have not even won a Grand Prix since 2012.
But Bottas, who became Lewis Hamilton's new team-mate at Mercedes earlier this month, believes another era of success is just around the corner.
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“Every year you can feel the team has gone more and more professional," said Bottas.
"Things are developing, even though sometimes the results don’t show it.
“I always say Williams has won so many championships that there’s no reason why it couldn’t win again.
Claire Williams is deputy team principal at Williams and is desperate for improvement
"I think it’s only for this team a matter of time.
“It’s a shame we couldn’t get together our first win or the title, but I wish all the best to everyone at Williams and a lot of success.
"And I hope you will get the championship rather sooner than later.”
But Bottas will race against Williams this year having signed a one-year contract at Mercedes.
The team were forced to hire a replacement for Nico Rosberg in the wake of his retirement just days after winning the F1 World Drivers' Championship.
And while the Finn has not had the same level of success as his German predecessor, he is confident of achieving his first victory at his new team.
"I’m really hungry for the wins and for us to win the title," said Bottas in his first appearance as a Mercedes driver.
Valtteri Bottas is hoping to follow in the footsteps of Nico Rosberg
"For me personally, I’m prepared to work really hard.
"I’m still young and fast.
"Obviously, Lewis [Hamilton] is going to be a great reference, he is a multiple world champion and everyone knows exactly how good he is.
"It’s going to be great to be his team-mate, also for me to compare to him, but first of all for us to work together and push the team forward."