My wife and I are visiting Rethymnon the first two weeks of August and would like to take a 3-6 day cruise to see some other Greek Islands. Where can I find information?
Try the dedicated cruise forum:
There is only one ferry that links Rethymnon to the Cyclades island, Santorini to be exact.
From there you'll be able not to cruise but travel to other islands of your choice.
From Heraklion the ferry goes to Santorini>Ios>Paros>Mykonos https://hellenicseaways.gr/en/routes/view/38