Set a budget for yourself. Cruises will differ vastly based on duration, standard and whether transport to Greece is included, so decide how much you are willing to pay and work from there.
Visit your local travel agents to discuss the holiday options if you wish to take a vacation including a cruise to Santorini.
Consider using sites which specialize in organizing tours in Santorini and other Greek islands. These include (but are not limited to) Cruise Compete, Cruises in Greece and Cruising Holidays.
Book your transport to Greece. Some cruise packages will not include your transport to Greece, so look into catching a flight. There is a major international airport in Athens, and smaller airports in Corfu, Crete, Rhodes and Santorini. A site such as SkyScanner (resources) is a fine way to check on availability and price of flights.
