Quick answer. Greece is in the EU. EU, EEA and Swiss citizens can work here with no permit. Everyone else, including UK passport holders, needs a work visa and residence permit arranged before arriving.
Do skippers and crew need a work permit in Greece?
EU, EEA and Swiss citizens: no work permit, register if you stay long term. Everyone else: you need a national (D) work visa from a Greek consulate, then a residence permit for work from the Ministry of Migration and Asylum. This is employer or host led and starts in your home country, so begin early.
Does the type of yacht matter?
On a bareboat charter (up to 12 guests who charter the yacht and hire a skipper) the rules above apply. On crewed charter, private yachts and superyachts, crew are often treated as seafarers and the route can differ with the flag and where the yacht is based, so confirm for that yacht. Working ashore follows ordinary work-permit rules.
Official source
Greek Ministry of Migration and Asylum and the Ministry of Labour (work for third-country nationals). Confirm the current rules for your nationality before you travel.
What we ask of you
Keep your nationality correct in your profile; it tells us your EU status.
If you hold a work permit for Greece, tick the work-permit box.
Tell us early if your right to work is not sorted, so we can help before your dates.
Important
Immigration rules change and vary by nationality. This is general orientation, not legal advice, and Quarterdeck is not an immigration adviser. Confirm your own position with the official source above before you travel. We will not place you in Greece if you do not hold the right to work. See also: Visas & work permits, overview.