The 27-year-old becomes new manager Pierre Sage's first signing ahead of the new season, adding experience and versatility to Palace's defence. Comfortable across the back line, Mingueza is capable of playing at both full-back and centre-back.
Mingueza arrives after three seasons with Celta Vigo, where he established himself as one of the club's key defenders. His impressive performances in Europe last season earned him a place in the UEFA Europa League Team of the Season after helping Celta reach the quarter-finals.
The Catalonia-born defender began his career at Barcelona's famous La Masia academy before making his first-team debut in 2020. He went on to make 66 appearances for the Spanish giants, winning the Copa del Rey in 2021 before joining Celta Vigo in 2022.
On the international stage, Mingueza has earned four senior caps for Spain and started in the 2025 UEFA Nations League final, underlining his growing reputation at the highest level.
Crystal Palace chairman Steve Parish believes the defender will be an excellent addition to the squad.
"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."
Mingueza said he was eager to begin the next chapter of his career in the Premier League.
"I'm really excited to be here. It's an honour to join Crystal Palace and I can't wait to see you at Selhurst Park," he said.
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