A yacht charter in the Mediterranean runs on a simple calendar. High season is summer, roughly July and August, when rates peak and marinas fill. Shoulder months, May, June, September, October, bring lower rates and saner harbors.
The Med prices on the APA model. Budget 25-35% on top of the base fee for fuel, food, and dockage, then VAT, which swings by country: about 6-13% in Greece, 20% in France, 22% in Italy, 13% in Croatia. Same boat, different water, different tax line.
Itinerary shapes the bill too. Island chains like the Cyclades keep distances short and fuel low. Hopping the French Riviera to Corsica to Sardinia burns more. Tell the captain your pace and let the APA follow it.
Book 6-12 months ahead for July and August; the best boats and the best berths go first. For shoulder months 3-4 months is usually enough, and gaps do appear in May and October. Greece books slightly later than the French Riviera, where August is effectively sold out by spring.
Sources: Songs in the Sails
Book the shoulder season and you get the same sea for 20% less.