B registrations: telling China, Taiwan, Hong Kong and Macau apart

At the fence in Frankfurt, a long-haul jet rolls past with a B registration on the fuselage. Air China? China Airlines? Cathay Pacific? If you only look at the prefix, you quickly end up with the wrong answer – because the B registration is shared by four registries: mainland China, Hong Kong, Macau and Taiwan. The good news: with two glances at the characters after the hyphen, you almost always know where the aircraft comes from. This guide shows you the four formats, their history and the typical traps when reading them.

B registrations: the short answer

All four territories use the nationality mark B. The difference is made by the registration mark after the hyphen:

• Mainland China: four characters, classically four digits (B-6136), now also with letters at the end (B-919A).
• Hong Kong: three letters, the first of which is H, K or L (B-HNK, B-KPB, B-LRJ).
• Macau: three letters, the first of which is M (B-MBM).
• Taiwan: five digits (B-18918, B-16701).

That means two questions are enough: How many characters follow the hyphen? And is the first of them a digit or a letter? Five digits mean Taiwan, three letters Hong Kong or Macau, four characters with a digit first the mainland. How registrations are built in general is explained in the basics guide Understanding aircraft registrations.

The four formats compared

Territory	Format	Example	Responsible authority	Typical airlines
Mainland China	B-1234, now also with letters at the end	B-6136, B-919A	Civil Aviation Administration of China (CAAC)	Air China, China Eastern, China Southern
Hong Kong	B-Hxx, B-Kxx, B-Lxx	B-HNK, B-KPB, B-LRJ	Hong Kong Civil Aviation Department	Cathay Pacific, HK Express, Hong Kong Airlines
Macau	B-Mxx	B-MBM, B-MCI	Macau aviation authority	Air Macau
Taiwan	B-12345	B-18918, B-16701, B-58301	Civil Aviation Administration (Taiwan)	China Airlines, EVA Air, Starlux

The table describes today’s system. Older photos and logbooks may show other formats – more on that in the history sections below.

Mainland China: four characters and new letters

In the registry of the People’s Republic, four characters follow B-. For a long time these were digits only, so registrations like B-6136, an A380 of China Southern Airlines that has since been retired. Because the number space gets tight in such a fast-growing aviation market, letters in the last positions have also been allowed since the end of the 2010s.

The best-known example of the new form is the Comac C919. The first production aircraft went to China Eastern Airlines in December 2022 as B-919A and flew the type’s first scheduled flight in May 2023. More C919s followed with B-919C, later also at Air China and China Southern with registrations like B-919X or B-919J. The manufacturer COMAC shows along the way how fond it is of playing with the connection between type designation and registration.

Does the first digit reveal the type?

In reference works, you read that the first digit after the hyphen points to the aircraft type or manufacturer. As a rough tendency, that’s true: many fleets were registered in blocks, and within an airline you often find long series of the same type. It’s not a fixed rule, though. Historically, for example, Airbus A300s and MD-82s also carried registrations with a 2 at the front, from a range that is often attributed to Boeing. If you try to guess a type from the registration alone, you’ll therefore be wrong regularly.

Provisional and factory registrations

One special feature for spotters in Shanghai or Tianjin is provisional registrations. According to common overviews, registrations with an L at the end stand for a provisional entry, with which no commercial flights take place. In addition, certain blocks with leading zeros are reserved for new-builds, such as Comac test aircraft – the C919 B-001J flew test programs in Shanghai-Pudong in 2022. You can learn more about such manufacturer and ferry registrations worldwide in the guide to manufacturers’ test registrations.

Hong Kong: B-H, B-K and B-L

As a special administrative region, Hong Kong keeps its own aircraft registry. The registrations consist of B, a hyphen and three letters, where the first letter is an H, K or L. For most spotters in Europe, that means: Cathay Pacific. Its fleet shows all three series side by side – for example the Boeing 777-300 B-HNK, the 777-300ER B-KPB and B-KQU, the A350-900 B-LRJ, the A350-1000 B-LXN and the 747-8F freighter B-LJA.

Originally everything ran under B-H, because the letters were taken directly from the old prefix VR-H. When the range filled up, B-K and then B-L were added. There’s no type rule behind it; newer aircraft simply end up in the newer series. That’s why at Cathay, older A330s still fly with B-H…, while younger A350s mostly carry B-L….

Besides Cathay, HK Express, Hong Kong Airlines, Greater Bay Airlines and cargo airlines such as Air Hong Kong also register their aircraft in Hong Kong. If you want to spot on location, you’ll find everything important in the guide Plane spotting in Hong Kong and in the profile of Hong Kong Chek Lap Kok Airport.

From VR-H to B-H

Under British administration, Hong Kong carried the prefix VR-H, a subdivision of the British prefix range. Cathay Pacific’s first aircraft, the Douglas DC-3 “Betsy,” flew as VR-HDB. With the handover to China in 1997, VR- was replaced by B-, while the letters behind it stayed. You can see this nicely on the Boeing 747-200 VR-HIB, which flew in a special livery for the handover in June 1997 and was later in service as B-HIB. If you have old photos of the legendary approach into Kai Tak in your archive, you’ll therefore often still find VR-H registrations there.

Macau: B-M

Macau works on the same principle as Hong Kong. Under Portuguese administration, Macau carried a prefix from the Portuguese range, most recently CS-M. With the handover to China in 1999, the territory switched to B-M, followed by two more letters. The registry is small, and the most important operator is Air Macau. Examples from its fleet are the A320 B-MCI in a special livery featuring Macau’s historic center or the A321 B-MBM in the “Macau Welcomes You” livery.

In Europe, you’ll rarely see B-M registrations. If you do, it’s worth a second look and a check against the registry, because such a small registry makes any sighting outside Asia something special. How to put such encounters in context is explained in the article How rare is my sighting?.

Taiwan: five digits

Taiwan keeps its own registry at the Civil Aviation Administration in Taipei. The Taiwanese regulation on the registration of aircraft stipulates that the registration consists of the letter B and a five-digit number. So the fuselage shows something like B-18918 or B-16701.

Within this framework, the airlines have established their own number blocks, by which you can often recognize them even before the logo:

• China Airlines: B-18… – for example the Boeing 777-300ER B-18007, the A350-900 B-18918 or the A321neo B-18101.
• EVA Air: B-16… and B-17… – for example the 777-300ER B-16701 or the Boeing 787-9 B-17881, the airline’s first 787-9.
• Starlux Airlines: B-58… – the first A330neo arrived in February 2022 as B-58301, and A350-900s carry numbers like B-58502.

Tigerair Taiwan and other operators also fly with five-digit B numbers. The blocks are airline habits, not a legal requirement – but they work excellently for a first classification anyway.

Why Taiwan switched to five digits

The prefix B originally belonged to the Republic of China. After the People’s Republic took over the Chinese seat at the United Nations in 1971, both sides kept using B. That threatened duplicate numbers. Taiwan had previously used numbers of varying length, including four-digit ones. After talks between the two sides in the 1990s, Taiwan switched to today’s five-digit format. Since then, the registries can be told apart at a glance.

At the fence: five steps to the right registry

For step 4, a look at the ICAO 24-bit address is worthwhile: it’s permanently assigned to each aircraft and helps when a registration in the photo isn’t legible. How to find a specific aircraft is shown in the guide Tracking an aircraft by registration.

Typical reading mistakes

• Mixing up the prefix with the airline. B- only means that one of the four registries is responsible. Only format and livery narrow it down.
• Overlooking digit-letter mixes. With new mainland registrations like B-919A, the last character quickly looks like a typo. It’s intentional.
• Ignoring leasing. Not every aircraft in a Chinese airline livery is registered in China. Leasing structures and registry changes happen; the article Offshore registrations and leasing explains the background.
• Dating old photos wrongly. A VR-H registration proves that the photo was taken before 1997 – or at least that the registration dates from that time. For CS-M, the same applies to Macau before 1999.
• Overlooking re-registrations. When an aircraft moves from Hong Kong to the mainland or abroad, it gets a new registration. More on this in the guide to re-registrations.

Why collecting pays off

For registration collectors, the B registries are an especially appealing field. Mainland China has one of the largest airline fleets in the world, Hong Kong and Macau offer compact, easy-to-survey registries, and Taiwan delivers, with China Airlines, EVA Air and Starlux, three long-haul airlines that regularly fly to Europe. Add exotics like the C919 or the ARJ21 and C909, respectively, which you hardly get to see outside China. If you want to spot on location, the profiles of Beijing Daxing and Shanghai Pudong give you a first overview.

How to build and structure your own collection is shown in the article Collecting registrations. An overview of the prefixes of all countries is offered by the guide to aircraft country codes.

Conclusion

The shared prefix B seems confusing at first, but follows a clear logic. Mainland China uses four characters, Hong Kong three letters with H, K or L, Macau three letters with M and Taiwan five digits. The formats grew historically – from colonial prefixes that were switched at the handover, and from the effort to avoid duplicates between the mainland and Taiwan. If you count the characters and look at the first one, you can place almost any B registration correctly right away.