Phuket is probably the most popular destination in Thailand after Bangkok. My wife and I went there specifically to dive and we were not disappointed with the diving. We were disappointed a little bit with the atmosphere though.
There are several ways to get there, but the most practical would be by air. You can take a car or a bus, but we were told that the bus ride would take up to 15 hours. Thai Airways has several daily flights to Phuket from Bangkok, and this only takes about 1.5 hours. The price isn’t too bad, either; we spent about U.S. $110 per person for round-trip tickets. It was well worth it to cut 13 hours each way off our journey. They had over 10 flights a day leaving for Phuket, and they were spaced about every 2 hours or so. You should be able to find a flight that meets your needs.
Phuket itself is a large island just off the coast and is surrounded by some of the most beautiful dive waters in the world. You can tell that at one time in the not-too-distant past, this island was an unspoiled paradise. Now it has become a bit touristy and is full of backpackers thinking that they are doing something different, even though they are following a well-worn trail. The huge influx of foreigners and tourists can bring many negative things. As with many popular tourist places in Thailand, you will find a rampant sex trade. If you stay around some of the nicer resorts or hotels, though, you won’t have to deal with it as much. If you are the type of person who likes a real native experience, Phuket definitely isn’t for you. Also, if you go out for a drink in town at night, expect to be approached by a hooker or pimp. Nice hotel bars are usually safe, though.
The food here is typical Thailand, which is to say GREAT! Thai food is just fantastic, in my opinion. Also, many of the people are very nice and very friendly. The hotels are getting more expensive, but they're still cheap compared to the west, as this is becoming such a popular area. You can still find some great deals, though; you just have to check around. Expect to pay anywhere from U.S. $20-$100 for a room. A nice, clean, air-conditioned, safe, resort-style hotel can be had for around $40-$50, though. Be sure to book ahead, though, as it does get rather crowded here on certain weekends, I’m told.
Well, diving was what I came for, and as far as diving goes, I wasn’t disappointed in the least. First of all, there are tons of dive operators, so prices stay low. An all-day trip with equipment and a few options can be had for $100 per person. You can pay less, but some of the operations might be less than safe. For $100, you can get a reputable person with modern equipment. There is also just about every option you could want available, so every diver should be satisfied. The water itself has fantastic visibility and a huge array of coral and aquatic life. There is even a fairly new shipwreck to dive--a ferry hit a coral reef in 1997 and sunk. There was no loss of life, and the ferry itself is in very shallow water.
If you have always wanted to learn how to dive, this can be a great place. Many dive outfits also offer certification and training courses, and you will find this much cheaper than in the west. All of the diving will be under 30 meters or so, and the waters are calm, so it would be great for beginners.
Overall, it’s a great place, although many of the places in town are becoming tourist traps. A family or couple can still have an exciting, fun, and cheap time here if you plan it right and use a bit of common sense.