Andrew
As a UK trained Teacher there have never been so many opportunities to teach abroad. New British Schools have opened their doors in almost every country you can think of providing an excellent choice for UK teachers to consider.
With so much choice it can be difficult and confusing to know where to begin.
A good place to start is to ask yourself what you are looking to achieve from your teaching experience.
If your main reason is to save money and not fussed about sightseeing/lifestyle then you may want to consider one of the more restrictive countries in the Middle East such as Kuwait or Saudi Arabia. These are both strict Muslim countries where alcohol is illegal. Kuwait is the more liberal of the two however neither country offers a rich travel experience. That said there are some top British International schools in Kuwait & Saudi so if you are happy to get your head down and work you could save a small fortune over a year or two. Generally speaking contracts in Kuwait are only for 1 year so you do not have to over commit, plus you could travel in your holidays which is what many teachers do working in these locations.
The Far East is a lot closer to Kuwait/Saudi than the UK so you are already half way there if you wish to explore that region.
The other benefit to a more restrictive country is that there is not so much to spend your money on. Teachers in Dubai/Abu Dhabi may also earn well but they are also far more likely to spend more amongst the glitz and glamour!
If money is not everything to you then you may wish to look further afield at somewhere like Thailand, Vietnam or Brazil. These countries generally offer richer travel experiences with more to see and explore. They also have significantly cheaper living costs than those in the Middle East although your wage will be lower in real terms. In most cases you can live very comfortably earning far more than the average local however coming back to the UK it will not translate back to GBP as well as a Middle Eastern package.
Savings are still possible on a smaller scale however you will probably have had a more enjoyable and fulfilling experience :)
