I just got back from 2 weeks there (one week on a liveaboard).
Like many others on my boat, I booked at the end of August thinking that the middle of the peak whale shark season would have the greatest likelihood of seeing whale sharks. I wish that before booking (instead of after), I had over-analyzed the Aggressor's weekly logs as well as potential impacts of La Nina on the likelihood of seeing whale sharks (we didn't see any -- the guide thinks the waters got too cold). If I get to go back, I think I'd go in June. We saw a lot of stuff, though and still had a great time. I also wish I was more patient to wait for another local (cold water Canada) diver could come with me so we could have longer dives in the West where temps were colder and the warm water divers I was with wanted to come up after 30 minutes, and I would have had a more experienced buddy that I dive with regularly.
For the first dive at Darwin, I wish I left my camera on the boat so I could first get experience with the way of diving there with the strong current but not drifting (of course, it was strongest at the entry of our first dive at Darwin, about 5 knots. With my octo in an octo holder, it was free flowing in the holder and if I let it dangle, so I had to hold it with one hand and the rock with the other until we drifted to a place more sheltered from the current and I could secure it in a better position. My camera was clipped across my chest at two points, and I didn't realize it was getting bashed on the rock while I was getting my catastrophic air loss under control.)
My side quest was to Floreana. It's the least inhabited of the islands you can stay on, so very local. I spent 3 nights there, and while my hosts were worried I'd get bored, I loved it. Very relaxing way to start the trip. I'm glad I didn't do a day trip which seemed very rushed (and more expensive). There's a lot you can do self-guided, and the island has a fascinating history. I stayed at Black Beach House (who also connected me with someone to arrange transportation to the island -- there aren't daily ferrys like other islands), and the snorkeling right of the beach (as well as La Loberia, nearby) was better than the dives I did on the liveaboard around Santa Cruz (the dives in the North and West are amazing, though!). A lot of biodiversity around Floreana. The biggest surgeon fish I saw on the whole trip (size of dinner plates) as well as huge parrot fish, lots of other fish, the most turtles I saw on the whole trip, playful sea lions I could enjoy without a bunch of other divers around, Christmas marine iguanas. Depending on the time of year, I was told you can also see penguins there sometimes. When I was there, there were bullheaded shark researchers staying next door so I was able to see some of the sharks they found and watch them release them. If I go back, I'd like to stay on Floreana for a week, and also make it to Isabela. I'd also get my freediving cert first
