Thailand diving charters are normally either of a 3 or 4 day period leaving from and returning to

Phuket or Thaplamu and visiting the Similan islands to the north west.
Thailand diving is very popular and the quality of boats vary greatly from small wooden boats to large motor cruisers.
The prices for Thailand charters also varies greatly but you generally get what you pay for and so if it sounds too good to be true it probably is. Good Thailand liveaboards normally cost from around 200 -300 dollars a day for a decent boatdependant on such things as the size of the boat, cabins, en-
suite bathrooms, air-con etc.
Thailand
diving is also done in the south
and Hin Daeng liveaboard trips are becoming increasingly popular in this area due to the fact they are a weekend trip.
Hin Daeng diving also includes diving in Koh Phi Phi and also at Koh Ha which featuressome unusual macro and great caves.
Southern Thailand diving is a great experience

as you get to dive Koh Phi Phi when all the daily divers have gone home.
Thailand diving on the west coast is done to 2 main destinations and the boats leave from and return to Phuket or Thaplamu near Khao Lak north of Phuket. Thaplamu is closer to the Similans than Phuket but there is a bus journey to your leaving point of 90 minutes. Phuket is further away from the Similans and is a 6 hour overnight crossing rather than the 4 hours from Thaplamu but it leaves directly from Patong beach.
Similan island liveaboard trips generally last 4 days and also visit the more northern islands past the Similan islands; Koh Bon, Koh Tachai and the famous
Richelieu rock.
The South Andaman sea trips or
Hin Daeng liveaboard trips include diving Koh Phi Phi and also diving Koh Ha along the way and these normally last 2-3 days