Hong Kong is one of the two special administrative regions of the People's Republic of China, the other being Macau.  From its early roots as a trading port in the 19th century, Hong Kong has developed into a leading financial centre.  Here's the map.

Marine resources in Hong Kong have been declining. They are threatened by overfishing, foreshore and seabed developments and water pollution. In July 1995, the Hong Kong Government announced a HK$108 million Artificial Reef Project aimed at enhancing local marine resources.  Deployment of vessels, concrete, quarry rock, and tyre reefs, totalling 168,700 had been deployed in Hong Kong under the Artificial Reef Project and other artificial reef deployment projects.   [Source: Hong Kong Artificial Reef Project]

• There are a variety of artificial reefs and offshore islands to dive on.
• Small coral communities can also be found along the eastern coastline, which make ideal snorkeling spots.

• Compared to other dive destinations in Asia, diving in Hong Kong has worse visibility often, cooler water is cooler and there is less to see.
• In the winter months, dive with semi-dry or dry suit.
• Most public beaches in Hong Kong have shark nets to protect swimmers from sharks. Once the sea surface temperature rises to above 23C, large sharks appear in local waters. There have been attacks, mostly around Clearwater Bay.
• Hong Kong has several marine animals that need to avoided. The most dangerous include sea snakes (rare), cone shells (common) and blue ring octopus (some).  Also, avoid lions mane jellyfish, white sea nettle and sea urchans.