Las Palmas sporting director Toni Cruz has confirmed Roque Mesa will join Swansea City with the deal to be announced this week.
The reported €13m deal has been sanctioned by both clubs and the player already sees himself at the Premier League club ahead of the new season.
"There is already a full agreement for the transfer of Roque to Swansea City and tomorrow (Wednesday) it should be official,” Cruz told reporters at a press conference.
Los Amarillos are also set for a future sell-on fee for the 28-year-old midfielder alongside bonus payments should he ever be capped for the Spanish national team, which has been rumoured in recent months.
Roma and Sevilla were among the other clubs interested in Mesa – Los Rojiblancos had a €10m bid rejected last summer with the player reportedly promised he would be allowed a move this year.