A senior Italy international at just 18-years-old, Ahanor joins Palace on loan from Atalanta until the end of the 2026/27 season.
The left-footed defender came through Genoa’s youth system and made his senior debut in Serie A as a 16-year-old, starting against Juventus in September 2024.
Having featured six times for Genoa, Ahanor last summer transferred to Atalanta, where he has since played 35 times in all competitions – including nine times in the UEFA Champions League.
The teenager impressed to such an extent that, in June, Ahanor won his first two senior international caps for Italy, keeping clean sheets in wins against both Luxembourg and Greece.
Ahanor said upon joining: “I'm very happy to be here and to be a part of this great family.
"To be at one of the best clubs for young players in the Premier League is something which makes me grateful and excited."
Chairman Steve Parish said: “Honest is an exciting young talent whose arrival offers further competition for places ahead of another European campaign at Selhurst Park.
"We are pleased to have him with us in South London.”