Container Tracking

Container tracking is the free lookup of a shipping container’s current status — terminal moves, vessel, position and estimated arrival — using the 11-character ISO 6346 number painted on the box, queried against the operating carrier’s public systems.

Here’s how the pipeline works. Terminals and vessels report events into the carrier’s system — gate-in, load, discharge — and the carrier republishes them on its tracking page. That has two consequences worth knowing before you start. First: the carrier’s own page is always the authoritative source; every aggregator resells its data. Second: events travel through EDI batches, not live feeds.

Find the number on the doors or either side wall: four letters, seven digits — e.g. MSKU 307703-8. The first three letters are the owner’s BIC code, the fourth is always U for freight containers, then a six-digit serial and a final check digit. The full format is defined by ISO 6346.

That last digit is arithmetic, not decoration. Each of the first ten characters converts to a value (letters map to 10–38, skipping multiples of 11), each value is doubled per position, the sum’s remainder mod 11 is the check digit (a remainder of 10 is written 0). One misread character almost always breaks the match — which is why a failed lookup usually means a typo, not a missing container. Two substitutions cause most of those typos, in both directions: the letter O read as the digit 0, and the letter I read as the digit 1. Because only one character is wrong, the arithmetic can usually point at which one.

To see whose box it is from the first four letters alone, without the whole number, the container prefix lookup lists every prefix we have checked with its owner and where its boxes are tracked.

Here’s the trap most tracking guides skip: the prefix names the owner, and the owner is not always the carrier. Roughly half of the world’s container fleet (47 % at the end of 2025, by the estimate in Triton’s annual report) belongs to leasing companies — Triton (TRLU, TCLU, TCKU…), Textainer (TGHU, TEMU, TGBU…), Florens, CAI — whose boxes are operated by whichever line booked the freight.

So a TRLU container may sail with Maersk today and MSC next quarter, and that is why searches like “Triton container tracking” lead nowhere: lessors run no trackers, because they never know which cargo is inside. The operating line is named on your booking confirmation or bill of lading — that is where you track. If you have neither document, the prefix alone cannot tell you: the same box carries different cargo for different lines through its working life.

Two attributions worth knowing because most prefix lists get them wrong: TCKU belongs to Triton, not Maersk, and TEMU belongs to Textainer, not Triton — both confirmed against the BIC register. And a TEMU-prefixed box has nothing to do with the Temu marketplace: parcels from the app are tracked with a courier number, not a container number.

Every company in the register has a page of its own: each prefix it holds, the check digit worked through for one number under it, and where its boxes are tracked.

Shipping lines: Maersk (MAEU, MRKU, MSKU, PONU, SEAU, MNBU, MRSU, SUDU); MSC (MSCU, MEDU, MSDU, MSMU, MSNU, MSPU, MSYU, GTIU); CMA CGM (CMAU, CGMU, ECMU, APZU, APLU, APHU, CNCU); COSCO (CSNU, CBHU, CCLU, CSLU); OOCL (OOLU, OOCU); Hapag-Lloyd (HLCU, HLXU, HLBU, UACU, UAEU, HAMU); ONE (ONEU, MOAU, NYKU, KKFU, KKTU, KLFU); Evergreen (EGHU, EGSU, EISU, EMCU, EITU); HMM (HMMU, HDMU); Yang Ming (YMLU, YMMU); ZIM (ZIMU, ZCSU, ZMOU); Wan Hai (WHLU, WHSU); PIL (PCIU, PILU); SITC (SITU); KMTC (KMTU); Matson (MATU); Crowley (CMCU); SM Line (SMCU).

Leasing companies, whose boxes are tracked with the line that books them: Triton International (TRLU, TCLU, TCNU, TCKU, TTNU); Textainer (TGHU, TEXU, TEMU, TGBU, MAGU, SEGU, GESU); Florens (FCIU, FSCU); CAI (CAIU, BEAU, BMOU); SeaCube Containers (INBU); Touax (TGCU); CARU Containers (CARU); UES International (UESU); Blue Sky Intermodal (BSIU); Raffles Lease (RFCU).

Most “container tracking” searches are really “where is my line’s tracker”. The table below answers that once: every prefix we have verified against the BIC register, line by line, with the official tracking page — and for each major line we keep a dedicated guide: Maersk, MSC, Hapag-Lloyd, OOCL and 14 more. All 85 owner prefixes we cover, held by 18 carriers and 10 leasing companies, are in the BIC register as we read it on 18 October 2026, each registered to its line or lessor or to a company of the same group (CBHU to Florens, COSCO’s leasing arm; NYKU to NYK Line and KKFU, KKTU and KLFU to K Line, two of ONE’s parents; EITU to Gaining Enterprise S.A., of the Evergreen group), and 15 are confirmed again by the company’s own document.

Not all trackers are equal, though. Some accept a deep link with your number already filled in; others ignore URL parameters entirely and want a paste. Of the 18 lines’ trackers we tested 7 in a real browser and published the result as a study with the raw data: 3 loaded the result directly, 4 loaded an empty form and ignored the number, and the other 11 we have not tested and do not claim either way.

With a manifest rather than a single box, paste the whole list. Each number has its check digit verified, its owner named and the place to track it given — the line’s own tracker for a line-owned box, the line on your booking for a leased one. Up to 50 at a time, checked in your browser.

Roughly half the world’s container fleet belongs to leasing companies rather than to shipping lines, so this is not an edge case — it is one of the most common answers a container number gives. Triton, Textainer, Florens, CAI and the rest own the steel and rent it out; they are not a party to your shipment, they never know what is inside, and they publish no tracking at all. Searching “Triton container tracking” leads nowhere for exactly that reason.

What you need is the operating line — whoever booked the freight for this voyage. It is named on your booking confirmation and on your bill of lading, and the same box can carry cargo for a different line next quarter, so the prefix alone will never tell you. If you hold a bill of lading but are not sure whose it is, its first four letters are the line’s SCAC code and name it on their own.

Once you have the line, the number tracks on that line’s own page exactly as a line-owned box would: the carrier reports events for every container it moves, owned or leased. These are the prefixes that work this way.

A working track returns a chain of standardized events. Read them once and every carrier’s tracker becomes legible — the wording shifts, the sequence doesn’t:

1. Empty pickup: the shipper collected the empty box from a depot — the trip officially starts here.
2. Gate-in: the loaded container entered the origin terminal; from this point it is in the carrier’s custody.
3. Loaded: craned onto the vessel — the event names the ship and voyage number.
4. Vessel departed: sailing confirmed; the ETA you see now is the carrier’s schedule, not a promise.
5. Transshipment: discharged and reloaded at an intermediate hub (Singapore, Rotterdam, Algeciras…) — only on routed sailings, and the most common place for delays.
6. Discharged: off the ship at destination; customs clearance usually starts here.
7. Gate-out: a truck took the box out of the terminal — and the free-time clock for returning it starts ticking — days inside the port are billed as demurrage, days outside it as detention.
8. Empty return: box handed back to the depot; the cycle is closed and tracking soon archives.

Between ports you also see the vessel’s AIS position. What you will not see: precise GPS of the box itself (only IoT-equipped premium containers have that), road positions after gate-out, and anything at all once the container leaves the ocean network.

The number validates, the carrier page loads — and returns nothing. This is where every other tracking site dead-ends, so let’s fix it properly. In order of likelihood:

1. The shipment is too new. Carriers publish the first event only after gate-in or loading, not when the booking is made. Booked yesterday means nothing to show yet — wait, don’t re-book.
2. The trip is over. Trackers archive shipments some time after delivery, and how long varies by line; an old number from documents resolves to nothing even though it was once valid.
3. The prefix belongs to a lessor. TRLU, TGHU and friends — see step 2; track with the operating line from your B/L instead.
4. A small operator without public tracking. Regional and feeder lines often have no tracker at all; ask the forwarder who booked the freight, or the port community system.
5. The box left shipping entirely. Containers sold for storage or conversion keep their painted numbers, but no system tracks them — a number that resolves to nothing usually means a retired box.

The order matters more than the list. For a carrier-owned box the first cause is overwhelmingly the most likely; for a leasing prefix it is the third, and no amount of retrying the same search will change either. Cause four is worth three worked examples, because it is the one people most often mistake for a broken tracker. Shipco Transport is a consolidator with no container prefix at all — third-party sites publish “SHPT” as one, and when we looked it up in the BIC register on 2026-09-17 it returned no entry, while other codes checked the same way the same day resolved normally. Vanguard Logistics tracks only by the house bill of lading it issues, and its portal is behind a login. Atlantic Container Line does have a real prefix, ACLU, but it is small enough that prefix lists routinely miss it.

Three identifiers get confused constantly, and pasting the wrong one into the wrong field is a top-three cause of “no results”. The container number (4 letters + 7 digits) identifies the physical box for life. The booking number identifies your reservation — one booking can cover many containers. The bill of lading (B/L) number identifies the shipment contract; the majors prefix it with their SCAC code: MAEU… is a Maersk B/L, COSU… a COSCO one.

Carrier trackers usually accept all three — in separate tabs or fields. Container numbers show one box’s moves; booking and B/L numbers show the whole shipment. If a freight forwarder gave you a “house B/L”, track with the container number instead: house documents exist only in the forwarder’s system. Telling them apart by shape is usually enough: a container number is four letters then seven digits; a bill of lading starts with the line’s four-letter SCAC code and runs longer; a booking reference is shorter and often all digits.

Carrier tracking is free, full stop: every major line publishes shipment status at no charge, no account needed. What costs money are aggregator APIs, billed per container — built for forwarders tracking whole fleets in one dashboard, not for checking a single box. If a site charges you to look up one container, it is reselling data the carrier gives away.

“Live” needs unpacking too. Tracking pages show the event feed — gate moves, load, discharge — updated as terminals report, with the reporting lag described at the top of this page. While the box is at sea, its position is the vessel’s AIS position, which several free ship-tracking maps display. True GPS of the box itself exists only on IoT-equipped premium containers. All of it works from a phone browser; Maersk, MSC and Hapag-Lloyd also ship mobile apps.

You have everything the pros use: read the number (the checker catches typos for you), identify the line from the prefix tables, track on the official page, and — when the result is empty — run the five-cause diagnosis instead of refreshing in frustration.

Where to go next: planning what fits inside the box you’re tracking? The CBM calculator turns carton sizes into container fill. Wondering what the size/type code on the door means? Start with types of shipping containers. And if a term on a shipping document stumps you, the glossary covers the vocabulary line by line. Every guide we keep is listed on the container guides page.