Chilwell returns to Selhurst Park from RC Strasbourg for a second spell, having spent the second half of the 2024-25 season on loan with the Eagles and won the FA Cup during that stint in May 2025.
The England defender, capped 21 times by his country, has also played for Chelsea, Leicester City and Huddersfield Town, and joined Strasbourg from Chelsea in September 2025 before making his way back to south London.
"It's amazing to be back," Chilwell said. "It's nice to see some familiar faces, and I'm just really excited to get back in, see the boys and the fans, and get going again."
Reflecting on his previous spell at the club, he added: "With this group, such a top group of boys, the manager, all the staff are all amazing. To win it with this group was amazing and then obviously the celebrations after with everyone were special as well. It was a brilliant night."
Netherlands international Quinten Timber has signed a five-year deal after arriving from Marseille. The 25-year-old, brother of Arsenal defender Jurrien Timber, has 13 caps for the Netherlands and was part of their squad at this summer's World Cup, giving Oliver Glasner's midfield fresh competition for places following Palace's Conference League triumph last season.
Completing the trio of arrivals, Crystal Palace signed Chilean winger Dario Osorio on a season-long loan from Danish side FC Midtjylland, with an option to make the deal permanent. The 22-year-old has made 121 appearances for Midtjylland since moving to Denmark in 2023, contributing 25 goals and 18 assists and winning two domestic trophies along the way. Born in the Chilean city of Hijuelas, Osorio broke through with Universidad de Chile before making the move to Scandinavia.
"I'm very excited to be here," Osorio said. "It's a dream I've had since I was a child to play in the Premier League – and I can't wait to get out there and play."
All three deals were completed after the 23:00 BST deadline through Premier League deal sheets, giving Palace fresh depth across defence, midfield and attack as they build on last season's first major European trophy and look to establish themselves as a fixture in the continent's competitions.