American vs. British curriculum for a first time expat in Hong Kong

Hi Mel-

It's much better that you'd be going from a British curriculum to an American curriculum, rather than the other way around. The American school system is, historically, much more welcoming and institutions usually make more of an effort to accommodate students who've had a slightly different curriculuar background. 

Also, as both your kids will still be below the age of 14 (the year in the British curriculum in which students begin to prepare for the A-level exams - college entrance tests) when you depart Hong Kong after 3 to 5 years, it will be far less of a problem. Especially for the four year old. 

When you transfer back to the American system your kids will most likely have to work a little harder to make up for some of the country-specific fundamentals that they may have missed (specifically, in classes like history or social studies and in Math - going from the metric system to the standard system), but otherwise there are curriculum that are far different than the two in question here. 

Perhaps the best thing to do though, would be to contact some of the American schools in your area, and to ask them specifically about how they would deal with the situation. 

As an alternative, consider enroling your kids in a school in Hong Kong with an IB curriculum. There are plenty, and this is a universal learning philosophy and style.

I agree with Steph. IB is commonly accepted worldwide, and the broad curriculum is quite a good foundation for pre-University preparation.