Hi Liberty - been to Cocos several times and led a group to Cocos + Malpelo two years ago on the Argo. Unfortunately it is no longer possible to do both destinations on the same trip but there are currently 8 liveaboards that go to Cocos (probably only 6 in 2011), while for Malpelo there are 2 boats that go from Panama and 2 boats from Colombia - the latter being slightly closer. Water temps at both can vary considerably, both at the surface and with cool thermoclines at various depths, however 5mm suit is generally adequate. Most surface temps hover around 27C (81F) while thermoclines at Cocos can take it down to as low as 21C (70F) and at Malpelo even cooler - they have site that is appropriately called the Fridge ! At Malpelo suggest 5mm with a vest and attached hood - layers make all the difference. Cocos is probably easier to dive, though some sites do experience some strong currents and it is not a destination I recommed to new divers- while Malpelo is definitely not for novices - the combination of water temps, strong currents, surge and remote location make this a challenging destination, but when it is at its best it is hard to beat.
Unlike Sudan, the water temps seldom reach the level where the sharks are forced to seek deeper cooler waters, and the huge schools of hammerheads can still be seen at both. Malpelo is renowned for its large schools of silkies, while Cocos gets even more diversity with Hammerheads, Silkies, Silvertips, Galapagos, Tiger sharks, Whale sharks, Dolphins, rays, tuna, huge schools of jacks and if you are lucky even bait balls now and again.
All drift dives but suggest you pack a reef hook for both. You can check out more info on destinatison on my website or contact me offline for availability. These are two of the top big animal destinations on the planet - you will love it. Dom
