Hong Kong - Sizes of Clothing
Clothes are usually sized according to the British sizes, unless you are shopping in a market and then it is a mixture of different countries. In general, larger sized clothing is difficult to come by. If you wear an American 12 or higher, you will have trouble finding clothes here in the local stores. It is possible to have shoes and clothes tailored, but that can be expensive. If you are very tall, finding clothing that accommodates your height may also be a problem.
Once you are in Hong Kong you can call the Community Advice Bureau and ask about whatever piece of clothing, in whatever size you need.
There is always internet ordering as well. Customs here isn’t a problem for items ordered elsewhere.