At present the main airlines are offering over 1000 direct flights to Kefalonia for Summer 2021.
Clearly we don’t know how the season will eventually turn out primarily regarding impact from covid restrictions, here on the island the cases figures are very low at present, primarily because we have been in lockdown since 7 November which will not be reviewed until 7th January 2021.
In Greece the vaccination program has just started with the majority of the population scheduled for vaccination by mid to late Summer, the most vulnerable will have been done before the tourist season commences. There will clearly be an update from Greece and UK regarding any covid related travel requirements before the first flights are due at the end of March.
Brexit changes are already clear, ensure you have 6 months validity on your passport, UK driving licence are OK for hiring cars, EHIC can still be used but additional health insurance is strongly recommended.
You will not need a visa for entry in 2021 but there will be changes to duty free arrangements.
Easyjet are starting flights late March & April with the main tourism season commences in the first week of May when all the other airlines commence direct flights to the island.
Most airlines are offering flexibility to transfer dates for free at present giving you piece of mind when booking. British Airways will start there scheduled flights (Saturdays) direct to Kefalonia from London Heathrow on 29th May and there last flight at the moment is 25th September.