Vagiannidis plays mainly as a right-back and joined Panathinaikos from the team's youth ranks. On 16 February 2020, Vagiannidis made his professional debut and scored his first goal, getting an assist as Panathinaikos beat Panetolikos 3–1 at the Olympic Stadium. In May 2020, Italian giants Inter expressed interest in acquiring the talented young player of Panathinaikos. The 18-year-old right-back had recently reached a verbal agreement with Panathinaikos to sign a new contract before talks were halted due to the Coronavirus pandemic.[2]
Inter Milan
On 5 June 2020, Vagiannidis has penned a four-year contract with Inter of Serie A. Inter will not need to negotiate with Panathinaikos to land Vagiannidis and will only have to pay a FIFA determined compensation amount of €400,000. The Greek full-back will reportedly earn around €300,000 per year in Milan.[3]
On 3 September 2021, Panathinaikos officially announced the return of Georgios Vagiannidis, who signed on a free transfer, a four-year contract with the club for an undisclosed fee.[6] Towards the end of 2024 talks between him and the club have begun regarding a new contract signed until 2027.[7]