Why does my Aliexpress tracking number change?
An AliExpress parcel is normally numbered three separate times, by three separate organisations, before it reaches a doorstep. The identifier a seller uploads first is a Cainiao logistics reference that exists only inside AliExpress's own shipping platform. When the parcel is consolidated for the international leg, the postal operator that accepts it issues a 13-character UPU S10 identifier under its own country code. On arrival, the delivery carrier may attach a domestic barcode of its own.
A changed number is therefore a record of those handoffs, not a sign that the parcel was lost, reshipped or swapped for another order. Each identifier remains valid for the leg that issued it, and the newest one carries the delivery scans.
Where each identifier comes from and who issues it
Three organisations can attach an identifier to a single AliExpress order, and only the first of them is AliExpress. The order number printed on the order detail page is a marketplace record of the purchase. It is never a shipping identifier and no carrier will accept it as one.
The second identifier is created when the seller books transport. AliExpress is a marketplace rather than a carrier, so the seller chooses the service. AliExpress Standard Shipping and AliExpress Saver Shipping are booked through Cainiao, which issues a logistics reference beginning with the letters LP. Other sellers book China Post directly, or use a freight forwarder such as 4PX, YunExpress, SunYou or Yanwen, each with its own numbering scheme. A handful of sellers of heavier or higher-value goods book an integrator such as DHL, FedEx or UPS, whose air waybill number never changes at all.
The LP reference is generated at booking, which happens before the parcel is physically collected. That is why it can return an empty result for its first day or two: it is a database record waiting for a scan, not evidence that a parcel exists. The general distinction between a booking reference and a scanned item identifier is covered in more depth in what a tracking number is and how it works.
The third identifier appears when the consolidated goods are handed to a designated postal operator. Postal networks do not carry another company's item numbers. The accepting operator opens its own record, issues its own barcode and takes responsibility for the item under Universal Postal Union documentation.
"The UPU sets out that postal operators can make use of CN 22 and CN 23 customs forms to move goods across borders and inject the goods into another postal operator's network." (HM Revenue and Customs, Customs treatment of post and parcel exports, 28 April 2025.)
That single sentence explains most of what buyers see. Injection is a deliberate commercial arrangement, and the injecting operator's identifier is the one that travels with the customs paperwork.
The four handoffs, and the identifier each one adds
Four handoffs sit between an AliExpress checkout and a delivery, and each one can attach an identifier the previous operator never sees. Only the first two are visible to most buyers on the order page; the last two often surface as a separate last-mile number.
| Handoff | Who issues the new identifier | Shape of the identifier | Timing after dispatch (estimate) |
|---|---|---|---|
| Seller to Cainiao or a freight forwarder | Cainiao, or the forwarder | LP followed by 12 to 14 digits, or the forwarder's own alphanumeric format | 0 to 3 days |
| Export consolidation to a designated postal operator | The accepting postal operator, or its office of exchange | 13 characters: 2 letters, 9 digits, 2-letter country code | 2 to 7 days |
| Arrival with the destination postal operator | The destination operator, where it relabels | The operator's own domestic barcode | At or shortly after customs clearance |
| Destination operator to a subcontracted last-mile courier | The final-mile courier | The courier's own consignment number | Final 1 to 3 days |
Not every parcel passes through all four. An item booked on an integrator's air waybill passes through none of them and keeps one number end to end. An item posted as ordinary China Post registered mail typically changes once, at the export handoff, because the destination operator continues to scan against the same UPU identifier rather than relabelling.
Why the last two letters are often not CN
The two letters at the end of a 13-character postal identifier are the ISO country code of the operator that issued the number, not the country the parcel left. A parcel bought from a seller in Guangdong can therefore carry a number ending SG, MY, BE, NL, LT, PL or ES, and none of that is an error.
Under UPU standard S10, an identifier is built as a two-letter service indicator, an eight-digit serial number, a single check digit and a two-letter country code, giving 13 characters in total (UPU standard S10, Identification of postal items). Because each designated operator administers its own block of identifiers, the suffix identifies the issuer and nothing else.
Two arrangements produce a non-Chinese suffix. In the first, the goods are line-hauled to a hub abroad and injected into a foreign operator's network there, so bpost, PostNL or Singapore Post accepts the item and numbers it. In the second, a foreign operator runs an office of exchange on Chinese territory and numbers the item before it leaves.
Extraterritorial offices of exchange "perform a wide range of postal functions that can vary by country, but generally include consolidating, documenting, and transporting outbound international mail." (United States Postal Service Office of Inspector General, white paper MS-WP-17-001, 31 March 2017.)
The service indicator carries information too. Ranges are allocated by product type: LA to LZ for tracked letter post, RA to RZ for registered letter post, CA to CZ for parcel post, EA to EZ for EMS express items, HA to HZ for e-commerce parcels and UA to UZ for other letter post items (S10 service indicator allocations). A number in the U range is a letter-post item carrying the thinnest scan set, which is why it produces so few events; a number in the C or E ranges is a parcel or express product scanned at more points along the route.
How long each identifier stays live
A postal S10 identifier cannot be reissued to a different item for at least 12 calendar months, so an old AliExpress number is not recycled onto a stranger's parcel while an order is still open. That non-reuse rule is part of the S10 standard itself and applies to every designated operator.
The three identifiers have different useful lifespans. The Cainiao LP reference keeps the full timeline from booking to delivery, because Cainiao aggregates events back from the operators it contracts with, and it usually stays the most complete single view of the shipment. The S10 identifier is authoritative from the export scan until the item leaves the issuing operator's network, after which it only keeps updating if the destination operator returns event data. The destination carrier's own number works on that carrier's website but rarely anywhere else.
Estimated timings, based on the structure of the route rather than on a published service standard: the postal identifier appears 2 to 7 days after dispatch, and a last-mile number appears at or shortly after the import customs event. Neither is a service commitment, and both stretch during the peak weeks around Chinese New Year and the November shopping period.
When two orders show the same tracking number
One identifier can legitimately cover two or more AliExpress orders, because consolidation numbers the parcel rather than the purchase. Two mechanisms produce it, and both operate at the first of the 4 handoffs above, before any postal identifier exists.
Combined shipping by one seller. When several items bought from the same seller are packed into one box, that box gets one identifier and every order in it is updated to show the same number. Both orders then move, clear customs and deliver together, and a single delivery scan closes both.
A consolidator's master number. Freight forwarders move many buyers' items in one container or one postal despatch bag. Where the master number is uploaded against the individual orders, unrelated buyers see the same code until the import scan, at which point item-level identifiers take over. The master number tracks the container, so its events describe the line-haul, not any one parcel.
The reverse case also occurs. A single order split across two parcels, which happens when a seller runs out of stock on one line, produces two identifiers against one order number.
Why a new identifier returns no data for its first few days
A newly issued identifier is a database record before it is a scanned parcel, and the gap between the two is estimated at 24 to 72 hours. Five causes account for nearly all of it.
The number was pre-advised, not scanned. Electronic advance data is transmitted when the label is generated. Until a physical acceptance scan follows, the operator's system holds a record with no events.
The number is being searched in the wrong network. An LP reference is not a postal identifier and returns nothing on a national postal website; an S10 number issued by bpost returns nothing on China Post's site. Each identifier only resolves in the network that issued it, or in an aggregator that queries several.
The destination operator has not ingested the item yet. Most destination operators create their record at the import office of exchange, which is often the same event as the start of customs clearance. Before that scan the new number exists in the manifest but not in the public tracking system.
The seller uploaded a placeholder. Marketplace rules push sellers to mark an order shipped within a short window, and a number entered to satisfy that deadline is sometimes replaced once the real booking is made. A number that changes within the first 48 hours and never produced an event is usually this case.
The item is on an untracked product. Letter-post products in the lightest weight bands may carry an identifier that is scanned only at export and at delivery, producing a long stretch with no events at all.
What a changed identifier does not tell you
A replaced number says nothing about distance covered, because 2 of the 4 handoffs above issue one while the parcel is still outside the destination country. Reading a new code as progress is the most common misinterpretation of the event.
It does not confirm that the parcel entered the destination country. Injection at a foreign hub issues a foreign identifier while the goods are still thousands of kilometres from the buyer. It does not confirm customs clearance either: the import operator's number is usually issued at the moment the item is presented to customs, not after it is released. It does not mean the seller reshipped the order, and it does not restart or extend the buyer protection countdown shown on the order detail page.
It also does not mean the old identifier is dead. Where the old number still resolves, it frequently holds the earlier half of the journey that the new number will never show, so the two together give the complete route.
How other marketplaces handle the same handoff
Parcels from Temu, Shein and eBay sellers in China pass through the same four handoffs, so the number changes for the same structural reason. The vocabulary differs more than the mechanism.
Temu routes most orders through consolidated line-haul and hands the final leg to a national operator or a regional courier, so buyers usually see one platform-level code followed by a domestic one. Shein operates its own consolidation and typically exposes a single platform code with the last-mile carrier named alongside it. eBay's managed international shipping programmes relabel at a transit hub, which replaces the seller's original number outright rather than adding to it. In the United States the outcome turns on how the goods enter the country. An item arriving as inbound international mail keeps its S10 identifier, and USPS scans against that number. An item flown in by a consolidator and entered as a domestic commercial package is relabelled instead, because the Domestic Mail Manual requires an Intelligent Mail package barcode on that traffic.
"IMpbs must be used on all commercial packages, and on other mailpieces of customers requesting extra services." (United States Postal Service, Domestic Mail Manual 204.2.1.1, accessed July 2026.)
That single rule explains why one AliExpress parcel acquires a USPS number and the next one does not, even when both were bought the same week from the same seller. The difference is the entry route, not the parcel (USPS Domestic Mail Manual 204).
When a changed identifier is a real problem, and who to contact
A number that changes is routine; a number that produces no scan for 14 days after its last event is not. Two thresholds are worth watching, both estimates rather than published guarantees: 14 days of complete silence mid-route, and any point at which fewer than 10 days remain on the buyer protection countdown shown on the order page.
The seller is the counterparty, not the carrier. The purchase contract is with the seller, and the marketplace dispute process is the only mechanism that returns money. Postal operators generally accept a formal enquiry only from the sender, which for an AliExpress order is the seller or its forwarder, so a buyer contacting a destination post directly will usually be redirected.
Open the dispute before the window closes, not when the parcel is confirmed lost. Buyer protection expires on a fixed date regardless of where the parcel is, and an expired window removes the refund route entirely. A dispute can be withdrawn if the parcel then arrives.
Ask the seller for the current identifier in writing. Where the order page shows an outdated number, the forwarder holds the current one. A message asking for the last-mile number and the name of the delivering carrier is more productive than a general complaint about delay.
Check the destination carrier's site with the newest number before escalating. Many stalled cases are simply an item that is moving normally under a domestic barcode that the marketplace page never refreshed.
What a replaced identifier gets confused with
Five distinct codes appear around a single AliExpress order, and only three of them are trackable. Confusing them accounts for most reports of a number that "stopped working".
| Code | What it identifies | Issued by | Trackable? |
|---|---|---|---|
| AliExpress order number | The purchase record | AliExpress | No, marketplace record only |
| Cainiao LP reference | The shipment booking | Cainiao or the forwarder | Yes, full timeline from booking to delivery |
| S10 postal identifier, 13 characters | The item in the postal network | The accepting designated operator | Yes, from export scan onward |
| Destination domestic barcode | The item inside one country | The delivering carrier | Yes, on that carrier's site only |
| Master bag or consignment number | The container, not the parcel | The line-haul consolidator | No item-level detail |
The practical rule is short: keep every number the order page has ever shown, search the newest one on the destination carrier's own site, and search the LP reference when the newest number goes quiet. Between the two, the full route is almost always visible.