Flight Information Regions in China Explained: The Nine Mainland FIRs, the Separate Hong Kong and Taipei FIRs, and Why the M503 Route Matters

China's airspace is the largest single national block on the Europe-to-Asia map, and almost every flight between Europe and Japan, Korea or South-East Asia either crosses it or routes carefully around its edges. Like every country, China divides its sky into flight information regions, the named boxes inside which one air traffic control centre is responsible for flights. Mainland China has nine of them. Two more that passengers often assume are 'Chinese' are in fact run separately: the Hong Kong FIR and the Taipei FIR.

This guide lists the nine mainland FIRs with their ICAO codes, explains who runs them and how foreign airlines get permission to cross them, looks at the Hong Kong and Taipei regions and the busy corridor between them, and explains the M503 route, the one piece of Chinese airspace routing that regularly makes the news. If you want the general concept first, start with our explainer on [what a flight information region is](/blog/what-is-a-flight-information-region-fir-explained); this is the China-specific companion to our post on the [flight information regions in India](/blog/flight-information-regions-in-india-delhi-mumbai-kolkata-chennai-fir-explained).

The nine mainland Chinese FIRs

China's Aeronautical Information Publication divides the country's airspace into nine flight information regions. Each is named after the city whose area control centre runs it, and each has a four-letter ICAO code beginning with Z, the letter assigned to China. Reading the codes is easy once you know the pattern: the second letter identifies the region (B for Beijing, S for Shanghai, G for Guangzhou and so on), and the last two letters are the FIR's own identifier.

• Beijing FIR (ZBPE): the north, including the capital's approaches and the corridor towards Mongolia and Russia.
• Shanghai FIR (ZSHA): the east coast and the Yellow Sea and East China Sea approaches used by flights to Japan and Korea.
• Guangzhou FIR (ZGZU): the south, bordering the Hong Kong FIR and covering the Pearl River Delta's mainland airports.
• Kunming FIR (ZPKM): the south-west, bordering Myanmar, Laos and Vietnam.
• Lanzhou FIR (ZLHW): the centre-north and much of the Tibetan plateau's northern approaches.
• Shenyang FIR (ZYSH): the north-east, bordering North Korea and the Russian Far East.
• Urumqi FIR (ZWUQ): the far west, the gateway for Europe-to-China flights arriving over Kazakhstan.
• Wuhan FIR (ZHWH): the central interior.
• Sanya FIR (ZJSA): Hainan island and a large area of the South China Sea.

Who runs them and how a foreign airline gets in

The Civil Aviation Administration of China (CAAC) is the regulator, and the Air Traffic Management Bureau (ATMB) provides the control service in each FIR. For an airline, the practical point is that a foreign civil aircraft can enter, cross or land in Chinese airspace only under an applicable agreement between its state of registry and China, or with specific CAAC approval. Scheduled airlines operate under bilateral air service agreements and seasonal or monthly block permits; charter, private and non-scheduled cargo flights apply for individual overflight permits.

The paperwork is more demanding than in most of Europe or North America. Published filing rules require the flight plan to be submitted at least 150 minutes before the estimated off-block time, a delay message if departure slips by more than 30 minutes, and a change message at least 45 minutes before any new departure time. Flights must follow the schedule or plan that CAAC approved; changing it needs permission before the flight, not after. None of this affects a passenger directly, but it explains why Chinese airspace is rarely used as an ad-hoc detour when airspace elsewhere closes: airlines cannot simply decide to route through it at a few hours' notice the way they can through, say, the [northern arc over the Caucasus and Central Asia](/blog/northern-arc-flight-routes-europe-asia-caucasus-central-asia).

Overflight planning inside China is also shaped by extensive military airspace, high traffic density on the eastern corridors and slot requirements at the big hubs. For Europe-to-Asia flights the usual entry is through the Urumqi FIR from Kazakhstan or Kyrgyzstan, then across Lanzhou and Beijing or Wuhan towards Shanghai and the coast. These routes have become more important since 2022, when the [closure of Russian airspace](/blog/flying-over-russia-airspace-ban-alternative-routes) to many Western carriers pushed Europe-Asia traffic south.

The East China Sea ADIZ

One term that trips up readers of Chinese aeronautical notices is the East China Sea Air Defense Identification Zone, declared in November 2013. An ADIZ is not a flight information region and not a no-fly zone. It is an area in which a state asks aircraft to identify themselves, usually by filing a flight plan and keeping radio contact, for air-defence purposes. China's AIP lists specific addresses to which flight plans for the zone should be sent. Airlines comply as a matter of routine, and passengers never notice. The zone overlaps the Shanghai FIR and, at its edges, airspace that Japan and others also claim to administer, which is why it was controversial when announced and why it still appears in route-planning notes.

Hong Kong FIR: separate, small and extremely busy

Hong Kong is a special administrative region of China, but its airspace is a separate flight information region, the Hong Kong FIR (ICAO code VHHK), run by the Air Traffic Management Division of the Hong Kong Civil Aviation Department rather than by the mainland ATMB. According to the department, the region covers about 276,000 square kilometres extending over the South China Sea. That is small by Chinese standards but it contains one of the world's densest clusters of airports: Hong Kong, Macau, Shenzhen, Guangzhou and Zhuhai, five major airports in the Pearl River Delta within a few dozen kilometres of each other.

Macau does not have its own FIR. The Civil Aviation Authority of Macao sits with the CAAC and the Hong Kong department in a tripartite working group that plans harmonised air traffic management for the delta, and new routes and handover points have been added over the years between the Hong Kong and Guangzhou FIRs for flights that overfly Hong Kong to land at Guangzhou or Shenzhen, and between Hong Kong, Macau and the eastern mainland.

For passengers, the Hong Kong FIR is the reason a flight from Europe to Hong Kong is handled by a different control service for its last half hour, and the reason delays in the delta tend to ripple across all five airports at once.

Taipei FIR and the M503 route

Taiwan's airspace is the Taipei FIR (ICAO code RCAA), administered by Taiwan's Civil Aeronautics Administration. It meets the Shanghai FIR across the Taiwan Strait, the Hong Kong FIR to the south-west, the Manila FIR to the south and Japan's Fukuoka FIR to the north-east. Flights between Japan or Korea and South-East Asia routinely cross it.

The M503 route is where the FIR map and politics meet. M503 is a north-south airway on the mainland side of the Taiwan Strait, approved through ICAO in the mid-2000s to relieve the congested coastal airway A470. It runs along the boundary between the Shanghai and Taipei FIRs; according to AeroTime's reporting, it lies about 7.8 kilometres from the median line of the strait, a line Beijing does not recognise. When the route opened, China made concessions, including moving it slightly west and limiting flight directions. Those have been rolled back in stages: in 2024 China began allowing eastbound flights on the W122 and W123 connecting routes, and on 6 July 2025 it activated W121, a third connector, which Taiwan's Mainland Affairs Council called a unilateral attempt to change the status quo. Taiwan's objection is practical as well as political: it says the routes run too close to the airways serving its outlying islands.

What this means for a traveller is almost nothing day to day. The routes are used by civil airliners under normal air traffic control, mostly on flights between Hong Kong or Macau and eastern Chinese airports, and there are no conflict-zone bulletins for the Taipei or Shanghai FIRs. The reason the topic belongs on a flight-safety site is the longer term: it is a live airspace dispute between two air traffic authorities that do not coordinate directly, in one of the busiest corridors in Asia, and any escalation in the strait would show up first as route changes and notices here, much as the Middle East crises of 2026 did in the [Tehran FIR](/blog/tehran-fir-flight-information-region-explained).

The Sanya FIR and the South China Sea

The ninth region, the Sanya FIR, is the one most passengers cross without knowing. It covers Hainan island and a large sector of the South China Sea, and it is the control region for the busy routes between Hong Kong, southern China and Singapore, Kuala Lumpur, Bangkok and Ho Chi Minh City. Its boundaries meet the Hong Kong FIR, Vietnam's Ho Chi Minh FIR, the Philippines' Manila FIR and Singapore's region in an area where several states have overlapping maritime claims. As with the East China Sea ADIZ, the civil aviation arrangements function regardless of the diplomatic ones; aircraft are handed between centres on published routes, and the disputes are fought in statements rather than in the control rooms.

Why FIR codes show up in flight-tracking and NOTAMs

If you look at a flight plan, a NOTAM or an airspace map, you will see the FIR codes rather than the names. A NOTAM beginning with ZSHA applies to the Shanghai region; one beginning with VHHK is Hong Kong's; RCAA is Taipei's. Knowing that the Z prefix is mainland China, VH is Hong Kong and RC is Taiwan lets you decode most of what you see. Our guide to [what a NOTAM is and how to read one](/blog/what-is-a-notam-how-to-read-airspace-closure-notices) explains the rest of the format.

For the overall picture of where Chinese airspace sits in the world's routing, our posts on [how airlines plan routes around conflict zones](/blog/how-airlines-plan-flight-routes-around-conflict-zones) and the [safest flight routes in the world](/blog/safest-flight-routes-in-the-world-2026) put it in context: Chinese FIRs carry some of the heaviest long-haul traffic on earth, have no active conflict-zone advisories, and are shaped more by permits, military airspace and the Taiwan Strait dispute than by the kind of closures seen over the Middle East in 2026.

In short

Mainland China has nine flight information regions, Beijing, Shanghai, Guangzhou, Kunming, Lanzhou, Shenyang, Urumqi, Wuhan and Sanya, all run by the ATMB under the CAAC and all requiring agreements or permits for foreign aircraft. Hong Kong runs its own FIR, Macau's traffic is handled inside the Hong Kong and Guangzhou regions through a joint arrangement, and Taiwan runs the Taipei FIR. The M503 route and its W121, W122 and W123 connectors are the most-watched piece of the map, not because flying them is dangerous today, but because they sit on the only FIR boundary in the region that is also a political fault line.