Mingueza joins on a free transfer from Celta Vigo and will be at Selhurst Park until the summer of 2030. A versatile operator capable of playing anywhere across the back line, the 27-year-old has won four caps for Spain and started for La Roja in the 2025 UEFA Nations League final against Portugal.
Born in Catalonia, Mingueza came through the ranks at Barcelona's La Masia academy, making his senior debut in 2020, winning the Copa del Rey the following year and going on to make 66 appearances before his move to Celta in 2022.
He brings plenty of European pedigree too, having been named in the UEFA Europa League Team of the Season for 2025-26 after helping Celta reach the quarter-finals.
Chairman Steve Parish welcomed the signing. "We are delighted to welcome a player of Oscar's quality and character to the club," Parish said. "His track record speaks for itself, with experience at the highest level for both club and country. We believe he will be a fantastic fit for Crystal Palace."
Speaking to Palace TV, Mingueza said the chance to work under Sage was a major factor in his decision.
"I think it's a really good place for me and for my family to be in London, and I'm really excited," he said.
"It's something that made me want to come to Crystal Palace - the new coach, the way he plays and that the last few years at this club have been really good. I hope we can continue going on and we will try to win more trophies."
On what fans can expect, Mingueza pointed to his passing range as much as his defensive qualities.
"I'm a player who tries to find a good pass. I like to drive forward and cross the ball. I believe I can defend higher and use my speed."
Mingueza already has familiar faces to lean on in the dressing room, having played alongside Yeremy Pino for the Spain national team and with Jorgen Strand Larsen at Celta. He also revealed he had experienced the Selhurst Park atmosphere before, having watched Palace play Brighton there two or three years ago.
"It was a crazy atmosphere," he said. "I remember the Palace fans screaming and jumping all the time. It was a really good atmosphere."