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. One misread character almost always breaks the match — which is why a failed lookup usually means a typo, not a missing container. The checker above runs this math as you type and even suggests the fix for classic O↔0 and I↔1 confusions; expand “show the check-digit math” on any valid number to see the worksheet.

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 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. Paste a leased prefix into the checker above and it walks you through exactly this.

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.

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 fourteen more. We verify 85 owner prefixes across 18 carriers and 10 leasing companies — each against two independent sources.

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. We tested every one in a real browser — here is what actually works:

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.
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, typically 24–48 hours after the box enters the system. Booked yesterday means nothing to show yet — wait, don’t re-book.
2. The trip is over. Trackers archive shipments 60–90 days after delivery; 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 checker above runs this same diagnosis on any valid number — expand “Container not found on the carrier site?” under the result, and it reorders the causes for your specific prefix.

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. Not sure what you’re holding? Paste it into the checker above — it recognizes B/L and booking formats and tells you where each one goes.

Carrier tracking is free, full stop: every major line publishes shipment status at no charge, no account needed. What costs money are aggregator APIs (roughly $2–5 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 6–24 h lag from 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.