Below you find details of how to check which cruises to the Galapagos Islands are available on your selected departure dates. Remember that the most popular cruises are booked up well in advance - you'll need to plan your vacation accordingly. You won't find another resource link this anywhere online - travel agents who regularly book cruises to the Galapagos Islands might want to bookmark here. Most of these availability databases are kept extremely up to date.
Consider that these are the actual providers (ground operators) of the Galapagos cruises. As such, you may well get the best rates if you approach them directly. If you can see that there is last minute availability, it's always worth asking for a discount.
AngerMeyer Cruises - MaryAnne, Sagitta, Samba, Diamante and the Beagle's availability can all be checked here. Sadly, you cannot check the availability of the other cruises that they offer (namely the Mistral, Nemo, Eric, Flamigo & Letty, and the SkyDancer). Click the "vessels" tab, then your preferred boat, and then the "availability" tab at the bottom.
Quasar - check the availability of the Evolution, Lammer Law, Parranda, Alta and Mistral cruise boats. At the moment, the links to check availability seem to be broken.
GalaCruises - here you should be able to check the availability of the Seaman Yacht.
Klein Tours - check the availability of the Coral 1, Coral 2 and the Galapagos Legend Cruises. Previously you could instantly check online - now you need to subscribe to the Klein Tours mailing list.