there are loads of possible options from Manchester flightwise. Do a check on Expedia or travelsupermarket to see what they come up with. There isn't a clear answer for whether package or DIY is best. I have usually gone DIY but took a package one year to Hua Hin as I couldn't beat it. Are you planning on a day or two in Bangkok or just wanting to go right to the resort?
have a look at Phuket or Koh Samui. If you like busy you will like Chaweng in Koh Samui.If you don't like busy but want a place with enough restaurants and bars to keep you from being bored then have a look at Bophut. The beach is not quite as nice as Chaweng though. Nice beach as well. Hua Hin can be reached by road from Bangkok but the beach is not great at all.
If you decide on the area you think you would like best then the next thing to do is to phone round TOs and get quotes and also price flights and accomodation individually.
Day to day costs in Thailand are cheap- but not quite as cheap as Goa. Hotel standards are far better though. Hopefully others will chip in with places they would recommend for children

Hi Debgreg,

If this is your first visit to Thailand, I would suggest a package (that includes transfers). Several companies such as Trailfinders and Premier will do a mix 'n match to suit your needs, including flights (times and routes to suit), transfers and hotels. This frequently works out as cheaply, if not cheaper, than DIY - especially Trailfinders. We have tried DIY and "package" and have just returned from a "bespoke" package. We couldn't match the prices by DIY

Most of Thailand can expect good weather over the new year.

Don't miss two or 3 nights in Banglok - the Grand Palace and Floating Market - other things shown on this site are not to be missed. Many people prefer Bangkok on the way back (to do some shopping etc). Judge for yourself, based upon flight timings and your personal preference. Personally, we prefer Bangkok first.

If you choose Samui, you may find that Chaweng is a little too lively (yes seriously) for 13 and 15 year olds (but there again I am getting old!).

Samui is beautiful, Phuket is also, perhaps, worth considering. Hua Hin would probably be too quiet.

Christmas and New year can be busy, so do your research, find your flights and book soon.

It is a totally different experience from Goa - but to me, much more civilised and interesting.

Good Luck and Enjoy!

Peter

Thanx it looks really nice but it is so much more expensive to get to than Goa, might have to give it a miss until it is just me and the other half going