The Spain international has emerged as one of Barcelona's top summer targets following his exploits for both club and country.
Last season, Williams scored eight goals and provided 19 assists in 37 competitive appearances to help Athletic win the Copa del Rey and finish in fifth place.
Williams went on to play a crucial role in Spain's successful Euro 2024 campaign, netting two goals and an assist in six starts.
Barcelona are not the only club to be impressed by Wiliams's performances, with Paris Saint-Germain, Chelsea, Liverpool and Arsenal believed to be among his admirers.
Barcelona receive William boost
It was previously suggested that Williams would not be open to a Premier League move, and it now appears that he is reluctant to join one of Europe's other major leagues.
According to Sport, Williams has turned down the opportunity to join his former Spain head coach Luis Enrique at PSG.
The French club's presidential sports advisor Luis Campos recently contacted the player's camp to establish whether he would be interested in the move.
Campos was ultimately given a disappointing response, with Williams turning down the proposal from the French champions.
Will Williams move to Barcelona?
While Barcelona have been given a boost, it is still unclear whether he will join Hansi Flick's charges or opt to stay at San Mames.
The Catalan giants are believed to be willing to activate Williams's €55m (£47m) release clause, and there has been a suggestion that the player is open to a move to one of the world's biggest clubs.
However, a recent report claimed that the 22-year-old forward could still snub a summer exit in favour of staying with Ernesto Valverde's side.
Williams is seemingly considering whether to stay at Athletic to compete in the Europa League alongside his brother Inaki Williams.