C4.59 Through-ticketing and Luggage Transfer¶
What is a connecting flight? What is through checked baggage? Guide to through checked baggage for connecting and non-connecting flights
If through checked baggage is not available for the first segment, your checked luggage may not be allowed on the plane unless the transit location of your second segment permits entry to collect checked baggage or agrees to check it through—this carries significant risk.
You must inform the first airline of this in advance. Generally, if the second segment allows 1 piece of checked baggage, the first airline may not accept through checking 2 pieces. Subsequent airlines have different requirements, so it depends entirely on the first airline’s procedures.
Recently, countless netizens have asked me the same question about through checked baggage and connecting/non-connecting flights. In fact, I mentioned this issue in previous Weibo posts, but the information may not have been detailed enough. Therefore, Shishengmiao decides to write a dedicated guide on airline connecting flights, non-connecting flights, and through checked baggage.
Reminder from Shishengmiao: This article is for reference only. All matters are subject to the official regulations of the airline and airport at the time of travel.
Guide to Connecting/Non-Connecting Flights and Through Checked Baggage
First, what is a connecting flight?It refers to a transfer flight purchased simultaneously (not separately). You must buy a single ticket directly from a ticket office for a journey: departing from Location A, transiting at Location B, and arriving at Destination C. Location B is the transit area, and transfers usually do not involve entry or overnight stays (some airports allow transit within 24 hours; specific rules are subject to the airline and airport). In short, flights with the itinerary A-B-C issued together on one itinerary receipt are connecting flights. Multi-stop transfers are also possible—you can inquire with the airline about through checked baggage for such itineraries.
Connecting flights can be operated by the same airline, partner airlines in an alliance, or airlines with a signed BIA (Baggage Interline Agreement, explained in the notes below). They must be purchased together, and all segments are typically listed on one itinerary receipt. Additionally, you can usually print boarding passes for all subsequent segments during the first check-in (Reminder from Shishengmiao: Some international transit areas do not have transfer counters or related facilities, so you may not be able to print subsequent boarding passes. Some transit airports may also not assist with rechecking baggage).
What is a non-connecting flight?Non-connecting flights are purchased separately. For example, you first buy a direct flight from Paris to Shanghai (second segment), then a direct flight from London to Paris (first segment). Or you purchase the first segment first, then subsequent segments later. In short, flights bought in separate transactions (each segment as an individual booking) are non-connecting flights.
What is through checked baggage?Most airlines worldwide have a Baggage Interline Agreement (BIA), which allows passengers on connecting flights to check their luggage directly to the final destination. For example: London → Paris → Shanghai. You can check your luggage through from London, no need to collect it in Paris, and pick it up directly upon arrival in Shanghai.
List of Baggage Interline Agreements (BIA) signed by domestic airlines:The two-letter code (IATA code) is a unified code assigned by the International Air Transport Association (IATA) to all countries, cities, airports, and IATA-member airlines worldwide. IATA’s full English name is International Air Transport Association. Airlines use two-letter codes—for example, Air China’s IATA code is "CA".
Reminder from Shishengmiao: The codes in the picture below refer to airlines. For example, Air China’s two-letter code is "CA", and "AA" is the IATA code for American Airlines.
As shown in the picture below, these are the global airlines with which Air China has a through checked baggage agreement (the letters are each airline’s two-letter IATA code):
如下图，字母是各个航司的二字代码
Reminders from Shishengmiao:
- Airlines without a through checked baggage agreement (BIA) do not offer through checked baggage. Most airlines have this BIA, but some do not—low-cost carriers generally do not provide through checked baggage services.
- Generally, through checked baggage must be arranged during the check-in for the first segment, and you will receive a baggage tag listing all airline codes. This baggage tag is extremely important—do not lose it and keep it safe. It is required for any issues related to your luggage.
- Connecting flights (with no entry or overnight stay during transit) are typically eligible for through checked baggage. However, even if airlines have a BIA, through checked baggage is not guaranteed. It depends on whether the airline staff at the check-in counter are willing to assist with through checking on the day. Airlines reserve the right to refuse, but through checked baggage is usually available for connecting flights. For non-connecting flights, through checked baggage is generally not offered, but it is not impossible—it depends on your luck. Airlines may assist if they choose, but they are not obligated to do so.
- Regardless of the type of ticket purchased, confirm all transfer-related regulations in advance to avoid being stranded due to failed transfers.
- When buying non-connecting flights, make thorough preparations in advance. This includes (but is not limited to) planning for unallowed through checked baggage, preparing for situations where the first segment counter does not print all boarding passes, figuring out what to do if subsequent boarding passes cannot be printed at the transit airport, confirming transit visa requirements, checking transfer time, verifying if the airport assists with rechecking baggage, and understanding other relevant regulations.
- Whether for connecting or non-connecting flights, confirm your baggage details during the first segment check-in. Ask if you need to collect luggage during transit, how to recheck it, if transit entry is required to pick up luggage, whether through checked baggage is available, and the final destination of your luggage. Carefully check the destination code on your baggage tag.
All the above information is subject to change. Please follow the official regulations of the airline and airport at the time of travel.
IATA Three-Letter Airport CodesThree-letter airport codes (IATA codes) are unified codes assigned by the International Air Transport Association (IATA) to all countries, cities, airports, and IATA-member airlines worldwide. IATA’s full English name is International Air Transport Association. In air transport, airports are referred to by three-letter abbreviations, known as "three-letter codes" or "airport three-letter codes." International airlines typically use two-letter codes—for example, Air China’s two-letter code is "CA."
This guide also applies to through checked baggage for transfers between domestic airlines—please apply it flexibly.
For example, the following IATA codes can be seen in the picture below:
As marked by Shishengmiao’s numbered labels and blue lines in the picture above, the explanations are as follows:
(1) YYZ: Indicates the through checked baggage tag was printed at Toronto Pearson International Airport on June 20th (the first segment). For successful through checked baggage starting from the first segment, the three-letter IATA codes of all subsequent segments must be printed on a single baggage tag.
(2) YUL: Indicates the transfer at Montréal-Trudeau International Airport.
(3) CDG: Indicates the transfer at Paris Charles de Gaulle Airport.
(4) PVG: Indicates the final destination airport, Shanghai Pudong International Airport—where you will collect your luggage upon arrival.
(5) The top of the tag will show the pinyin "SHANGHAI PUDONG," which is the destination of your itinerary.
(6) As shown in the picture, the part following Shishengmiao’s first blue line refers to: Flight number.
(7) The part following the second blue line refers to: Time.
(8) Baggage tag number.
In other words, if you are transferring back to China with through checked baggage, the baggage tag must include the three-letter IATA codes of all transit airports. Check each code carefully, especially the one for your final destination. This baggage tag is very important—please keep it safe.
Below is the table of global airport three-letter codes:
Below is the table of three-letter codes for domestic airports in China:
