Hey everyone

I'll be visiting China in May for work, and I'll have 2 free days in Beijing and 3 free days in Shenzhen.

Does anyone have recommendations for dive centers in those areas?

There is very little to nothing in northern China. You can dive near Dalian, but they have absolutely pillaged the near shore animal life in this area. In the south you can dive Hainan island (somewhat akin to the "Hawaii of China") but you will be diving with lots of other divers, and the average diver is much more likely to be on the reef than cruising over the top of it. This is changing slowly, but there are now more artificial reefs in Hainan than healthy natural reefs left because of this.

Go see the Great Wall from Beijing (I was there again about two months ago) - still a very good experience. For your time in the south, if you really want to get wet, after having experienced Hainan, I would recommend traveling to HK, and trying the diving there. It's not excellent, but it's not horrible either. And you will be able to find experienced dive shops that will show you some of unique diving available.