The transfer plugs a gap the Cherries had marked as a priority since Marcos Senesi left on a free transfer for Tottenham earlier this month: Bournemouth will pay an initial £21.4m for the Portugal international, 22, with a further £4.3m available in add-ons, taking the deal's total value to almost £26m.
Getting the move over the line took time, with Bournemouth having watched Silva for much of the window before an agreement was struck. Club sources say the deal only came together after Benfica's Thursday win over Swiss side St Gallen in Europa League qualifying — a game in which Silva, who turned down a new contract in Lisbon this summer, captained the side in what looks to have been his farewell appearance following a decade at the club.
Since breaking into the first team in 2022 he has made 183 appearances in all competitions, featuring in the Champions League, Europa League and Club World Cup, and has earned 20 caps for Portugal, including selection for the 2022 World Cup and Euro 2024 squads. He was left out of Roberto Martinez's squad for this summer's tournament, however.
Silva once carried a release clause as high as €100m and had drawn interest from Liverpool, but Bournemouth are understood to hold an edge through Silva's existing relationship with the club's president of football operations, Tiago Pinto, who previously held the equivalent role at Benfica.
The defender follows striker Alvaro Rodriguez, signed from Elche in a deal worth up to £25.7m, as Bournemouth's second arrival of the window. Having sold more than £200m worth of players last year, the Cherries are aiming for a calmer summer under new head coach Marco Rose, who succeeded Andoni Iraola after the Spaniard's three-year spell on the south coast came to an end.