Yalong Bay-Hainan, China
Hainan, a tropical island roughly the size of my homecountry the Netherlands, is China's most southern province. Only a fraction of it's 600km coastline has been touristically developed. From this beach area called Yalong Bay, you can take a small speedboat out to the coral reefs on a couple of minutes distance only. I found the diving there relaxing and better than the general comments I have read on the internet. The diving scene is nevertheless indeed in a very basic state.