Hey! I'm in the same situation as you... looking for a new place to go out and explore. I spent last high season in Phuket Thailand. The lifestyle is a bit of a culture shock but I really did enjoy the culture, language and of course the food! The diving south of Phuket (Racha Yai) is great for teaching students and some dive sites are good for more experienced divers. Racha Noi, gives chance for Manta's and dive sites around Phi Phi Island are also quite nice and relativiely undamaged in my opionion... the coral life is quite colorful and nice. also good chances for turtles and Sharks. Further north, the Similan islands have very nice dive sites, cool critters and good chance for Mantas and Whale Sharks... cross your fingers!
I would say Phuket is a great option... central to all those areas I mentioned and if you work as a freelance intructor, depending on day boats or liveaboards, you can get in a variety of trips. I liked the different day boats and the chance to meet many instructors. A very fun atmosphere at work! The cost of living is quite low. I would say even cheaper than it was to be in Utila. I paid maybe 350$ tops for a beautiful share house in Patong Beach. Further out, there is definilty cheaper places to stay. Most day boats have breakfast and lunch on board so the only meal I usually paid for was dinner at night. You do however need a work permit to work in Phuket. Other areas like Koh tao you do not need one... or it atleast hasn't been inforced. There is lots of teaching opportunity there I've heard (a factory) but the diving isn't as great, which is why I never made it out that way. Anyways I'm missing thailand right now. Once you get used to the commerical aspect of it, the job is nice... the money isn't great, but I'm sure you would agree, most instructors aren't in it for the money profit. But you can definilty get by and there is good opportunity to make good money. Having more languages is also helpful. Anwyays if you have any questions about Thailand feel free to drop me a line. Got lots of info on the island, dc's, work permits... I'm selling my company at the moment. I've also worked on catalina island in california... cold, but a nice change and neat diving. Australia GBR or ningaloo reef also has nice diving. Cairns is a very busy dive area. Not sure how the sites are there now... Been a few years since I worked there... but lots of teaching opportunities there!
anyways good luck! were you working in Utila? I just did a trip there in November. Wasnt that impressed with what I saw. I thought Roatan was a bit better.
