On 15 February 2016, Panathinaikos officially announced the loan of Christos Donis to Swiss club Lugano until the end of the season, with a contract option to purchase him.
[8] On 30 April 2017, he helped his club to sealing a 2–2 away draw against Asteras Tripolis, with a wonderful free kick, concluded his exceptional performance in the second half of the 2016–17 season.
[10] On 6 April 2019, he scored his first goal for the 2018–19 season was in the right place at the right time to convert an excellent pass from Italian striker Federico Macheda, as Panathinaikos moved to within five points of fifth-placed Aris after claiming a solid 2–0 home win over the Thessaloniki club at the Olympic Stadium.
[14] On 24 January 2023, after spending most of the winter training with Polish Ekstraklasa side Radomiak Radom, Donis signed with them until the end of the season, with a two-year extension option.
[15] Donis is the son of the former footballer and current manager, Georgios and the elder brother of Anastasios, who plays for the Cypriot club APOEL.