February is one of the best months for the west coast of Thailand and also for the Mergui Archipelago. There are enough dive sites to keep you busy for a month if you have enough money
You've got the Similan Islands, Koh Bon, Koh Tachai, Richelieu Rock, Surin Islands, the Mergui Archipelago (Myanmar), Hin Daeng, Hin Muang, Phi Phi, all the local Phuket sites (Shark Point, Racha Islands, King Cruiser Wreck, Anemone Reef, Koh Doc Mai) and more.......
Thailand Dive Sites
Mergui Archipelago Dive Sites
Malaysia - well, the No.1 attraction is Sipadan of course. February is not the best month there, the weather can be unsettled and visibility is not the best, but nevertheless the resorts are quite busy and the diving is still great. At Mabul you also have excellent muck diving (looking for strange critters).
Sipadan Dive Sites
Mabul Dive Sites
Further afield, but still in Asia, you have Raja Ampat. Becoming more popular, but not so easy to get to and rather devoid of rampant tourism. Raja Ampat is just to the east of North Sulawesi, part of West Papua, Indonesia, formerly called Irian Jaya. Not been myself, but people say it is an amazing area to dive and explore.
Raja Ampat Dive Sites
There's some food for thought..