LONDON (AFP) - Wales captain Ashley Williams joined Everton from Premier League rivals Swansea on Wednesday (Aug 10) to fill the gap left at Goodison Park by the departure of fellow central defender John Stones.

Tuesday saw England international Stones move to Manchester City for a a reported £47.5 million (S$82.8 million).

Williams, 31, has joined for an undisclosed fee on a three-year deal thought to be worth significantly less than the value of Stones' move.

Leaving after eight years with Swansea, Williams said he was looking forward to learning from Everton manager and former Netherlands defender Ronald Koeman.

"For me the new challenge was something I felt I needed, so I'm delighted to have joined Everton," Williams told Everton's website.

"Everton is a great club with an unbelievable manager - a world legend in football - and I believe the club is going in the right direction.

"This is something I wanted to be a part of.

"I look forward to seeing what the manager's plans are for me and the team. He's been one of the greatest centre-halves to ever play the game, so I look forward to learning from him and seeing what he can teach me."

Meanwhile, Koeman was happy to welcome Williams to Liverpool-based Everton.

"We wanted to bring in a strong player in the central-defence position, a player who knows the Premier League and Ashley fits the bill for us very well," he said.

"He is an experienced defender and the kind of player we need in the team. He is a leader. He showed this at Swansea and he has shown it for his country and he is looking forward to his new challenge here at Everton."

Williams starred for Wales during the shock run to the last four of Euro 2016 and has been a cornerstone of Swansea's defence since he joined from Stockport in 2008.

After seeing Williams rise through the division of English football with the Welsh club, Swansea chairman Huw Jenkins was sad to see him leave for Merseyside.

"We are disappointed to lose Ashley. It is definitely not something we wanted to happen," Jenkins told Swansea's website.

"But having turned down Everton's initial offer, Ashley expressed his desire for a new challenge at this time of his career.

"Taking into account the excellent service Ashley has given this football club over the last eight years, including as club captain, we reluctantly agreed to his request to join Everton after they made an improved offer.

"It goes without saying that we wish him the very best with his new challenge and thank him for his services."