That's according to Ekathimerini, Ukrinform reports.
They are expected to hold talks with Ukrainian President Volodymyr Zelensky and Defense Minister Oleksii Reznikov.
Sakellaropoulou will have a private meeting with Zelensky and will later be joined by their respective delegations.
Panagiotopoulos' talks with Reznikov come weeks after Greece started shipping BMP-1 infantry fighting vehicles to Ukraine, as part of the "circular exchange" with Germany that is supplying Athens with a total of 40 Marder IFVs.
The arrival of the first tanks was announced by Ukrainian Foreign Affairs Minister Dmytro Kuleba on October 19.
The Greek president's visit was originally scheduled for mid-October, however, the appointment was rescheduled due to unspecified obstacles. The trip was not announced in advance for security reasons, Greek daily Proto Thema reported.