Pilotage is compulsory in Hong Kong Waters.

In general, ship, other than an exempted ship, while navigating in Hong Kong Waters shall be under the pilotage of a licensed pilot(s) if it is 3,000 gross tons (GT) or over, 1,000 GT or more carrying certain classes of dangerous goods or a gas carrier. Schedule 1 to the Pilotage Ordinance Cap.84, assessable at the link below, gives details of ships subject to compulsory pilotage.
<https: www.elegislation.gov.hk="" hk="" cap84?pmc="1&xpid=ID_1438403567418_002&m=1&pm=0>

Pilotage service in Hong Kong is operated by commercial enterprises and available 24 hours a day. Information on the service provider is available at the following link:
<https://www.mardep.gov.hk/en/public-services/shipping-directory/index.html>

Ships carrying a pilot should fly an international code flag "H"

International Code Flag
International Code Flag "H"

Government Departments of both Hong Kong and Shenzhen has signed the framework agreement on co-operation in Mirs Bay pilotage. Vessels that are required to be under compulsory pilotage as stipulated in the laws of both Hong Kong and Shenzhen will be piloted by a single Hong Kong or Shenzhen qualified pilot throughout the entire voyage to or from the Shenzhen East Port Area through Mirs Bay.

Hong Kong has nine pilot boarding stations :

Hong Kong has eight pilot boarding stations

1 Ha Mei Wan, west of Lamma Island An area of 0.5 nautical mile radius centred by position
latitude 22°11.908΄ north,
longitude 114°05.447΄ east.
2 Turning buoy in the Tathong Channel An area of 0.4 nautical mile radius centred by position
latitude 22°15.908΄ north,
longitude 114°15.814΄ east.
3 Lam Kok Tsui (Black Point) in Urmston Road An area of 1.0 nautical mile radius centred by position
latitude 22°24.925΄ north,
longitude 113°53.347΄ east.
4 Entrance to Tolo Channel An area of 0.5 nautical mile radius centred by position
latitude 22°29.508΄ north,
longitude 114°19.848΄ east.
5 Ngan Chau in East Lamma Channel An area of 0.5 nautical mile radius centred by position
latitude 22°12.958΄ north,
longitude 114°09.847΄ east.
6 Ping Chau in Mirs Bay An area of 0.5 nautical mile radius centred by position
latitude 22°32.800΄ north,
longitude 114°23.600΄ east.
7 Crooked Island in Mirs Bay An area of 0.5 nautical mile radius centred by position
latitude 22°33.500΄ north,
longitude 114°20.200΄ east.
8 Shek Ngau Chau in Mirs Bay An area of 0.5 nautical mile radius centred by position
latitude 22°29.700΄ north,
longitude 114°26.540΄ east.
9 South of Cheung Chau Island An area of 0.7 nautical mile radius centred by position
latitude 22°09.663΄ north,
longitude 114°03.055΄ east.

The Director of Marine is the Pilotage Authority and he is advised on all pertinent matters by the Pilotage Advisory Committee.