Buiszie: The best time for diving is Aug - mid Nov. That is when the marine life is most abundant and when the whale sharks are present in the north. Hammerhead populations are prolific then. This coincides with the arrival of the polar Humboldt current as well as the Cromwell current from the west. They bring a smorgasbord of nutrition so marine life has a feast. It also means less visibility and colder water.
As there are now only 3 liveaboards operational in Galapagos: Aggressor, Galapagos Sky and Humboldt Explorer. Well, let me qualify as Deep Blue is still considered 'operational'. I know a lot of agencies continued to sell Deep Blue. Others offer dive destinations around the world. We only offer Galapagos. So after nightmares with many clients onboard Deep Blue in Sept-Oct 2013, we ceased to offer Deep Blue the second week of Sept 2013 due to the sad shape of the vessel and the poor management. Unfortunately, out of 49 clients scheduled onboard between Sept-Dec, we were only able to move 12 as Sept-mid Nov is often booked in full 2 years in advance.
I was so weary of dealing with the tragedy of clients' once in a lifetime trip being so disappointing and an indifferent owner. So many refunds promised or in order that never happened because the owner refused to honor his commitments to refund. As far as I know, they've had no Nitrox since July 2013 and the generators and motors just continue to worsen on the departures they have made this high season. It seems they've cancelled more departures in less than a week, usually 2-4 days in advance, than have sailed this high season. I am so happy I have not subjected anyone to the nightmare that vessel has become. Perhaps after they are marketed by a fleet who intends to make an enormous investment to replace the motors, the generators, the Nitrox membrane, etc the rebranded Galapagos Master will once again be operational and worthy of the price it takes to dive Galapagos. It's too expensive not to be worth it and short of boat problems, it is worth the price of admission. At least 2 other liveaboards are supposed to become operational, but we once made the mistake of pre-selling a boat that never became operational, so are now quite cautious. As a result, this year, we had no one onboard the liveaboard that was booked from June on and has not yet sailed. I'm sure they'll eventually work out their issues, but until then being cautionary has been quite beneficial this year, both in terms of client inconvenience/disappointment and in terms of not spending most of my time dealing with problems. So until others are operational or in good shape, I would recommend sticking with the 3 tried and true liveaboards: Aggressor, Galapagos Sky and the Humboldt Explorer.
Water temp depends on when/where you go. Surface temps tend to range from 18C / 64F to 26C / 76F. If you are on a western itinerary, Cabo Douglas or Punta Vicente Roca may be as low as 13C / 54 F. At most sites (except Darwin), thermoclines can be in the 16C / 62F range. Waters are warmest Feb-mid May and coolest July - mid Nov.
To arrive, you fly to either Guayaquil or Quito in Ecuador and from there, fly to Galapagos. Do visit our website for lots more information.