First of all, do not forget to bring along your original skipper’s license, a signed sailing resume and the booking confirmation.
Regarding your luggage: As there is only limited storage space on sailing yachts try not to bring hard shell suitcases and try to travel lean.
Do not forget to bring your sailing gear or, in case you do not own this, bring a windbreaker jacket and trousers. Even during the summer months, the weather can get rough on open sea or at least breezy in the evening.
We are sure it seems obvious to you, but bring along sun blocker, sunhat and sunglasses. The Greek sun is very strong.