Get the right Chineses visa
For legal, immigration and visa purposes Hong Kong and China are two separate countries. While Hong Kong offers visa free access to citizens from the US, Europe, Canada, Australia, New Zealand and more countries, China doesn’t and almost everyone will need a visa.
There are several types of visa available. If you are travelling to Shenzhen or that region, citizens of some countries are able to get a Shenzhen visa on the spot at the Hong Kong/China border. Similarly, there is also a Guangdong group visa that allows access to a slightly wider region for groups of three or more. There are numerous restrictions and rules applied to both these visas which are explained in detail in the links below.
For visits further afield you’ll need a full Chinese tourist visa. Yes, these can be obtained in Hong Kong, although on rare occasions, the Chinese government agency in Hong Kong that deals with visas chooses to enforce its rule that foreigners can only obtain a Chinese tourist visa from the Chinese embassy in their home country. This can almost always be circumnavigated by using a local travel agency.
Remember, if you are plan to travel in to China, back out to Hong Kong and back into China again you’ll need a multiple entry visa. Macau is separate to Hong Kong and China visa rules and allows most nationals visa free access.
Travel between Hong Kong and China
Hong Kong and China are well connected and how to travel to China from Hong Kong depends on where you are going.
For Shenzhen and Guangzhou the train is the quickest form of transport. Hong Kong and Shenzhen have metro systems that meet at the border while Guangzhou is a short two hour train ride with services running frequently.
Overnight trains also connect Hong Kong to Beijing and Shanghai but, unless you’re keen for the experience, regular flights are a much quicker and, often, not much more expensive way to reach China’s flagship cities.
From Hong Kong you can also reach most of China’s other major and mid size cities with Guangzhou airport offering connections to smaller towns in the country.
If you’re looking to visit Macau the only way is ferry. Ferries between the two sister SARs run almost constantly and take just an hour. The ferries run a reduced service overnight.