greek island ferries or other, in March 2013

Nope, you haven't missed anything. This chart of ferry routes http://www.greeceathensaegeaninfo.com/ferry-info-greece/greek-islands-ferry-chart.htm shows clearly that Mykonos is not on a main route to Santorini in other words, it isn't a journey that regular GREEKS take or want to take. Thus, they are only connected during tourist season. If you're willing to take a day (and see 2 interesting ports in the bargain) there is a work-around. 6 days a week at 1415 (2:15 pm) there's a 75-minute BLUE STAR ITHAKI ferry to SYRos ... This island, visited 99% by Greeks only, has a spectacular harbor city Hermopolis, with a gorgeous main square ... you could enjoy late afternoon & a dinner there, then take the 9:25 (21;25) BLUE STAR ferry to NAXOS arriving 23:25. Stay right on seafront at Hotel Coronis... then in the AM, explore Naxos' charming port town (you'll vow to come back) and get the 12:55 BLUE STAR daily ferry to Santorini, arriving about 1500 (3 pm). Of course, all that will cost you more than Aegean flight to Athens, quick transfer, back to Santorini. Maybe u should re-think going to Mykonos in March... unless you are set on going to ancient Delos, which I'm willing to bet you're not you have been seduced by all the promotion about Mykonos' night life, and beaches. Well good luck on beaches in March! and night life is nil too. Santorini is a must-see for newcomers, for The View, but otherwise you might research for places that have interest during non-beach months.

By the time you reach Santorini using the alternate route suggested above I'm pretty sure you will have spent a lot more money, and more importantly time, than if you fly. Right now in March Aegean Airlines has fares as little as €39, all taxes included, for flights from Mykonos to Athens, and €65 for Athens>Santorini. That's €104. Figure out what it will cost to take the ferry and add in the cost of a hotel and various meals. Flying is cheap. If by chance there's no connecting flight try checking the Olympic Air website. It means collecting your bags and re-checking them for the onward flight, but it might be the only way you can make it work. Give yourself 2 hours between flights for this. Check the websites for each airlines for pricing but also check www.airtickets.com. This booking website will help you find what you need and will combine airline companies if needed.