Number → carrier → vessel & ETA
Container Tracking
Every ocean container broadcasts its position through the carrier’s systems, and the lookup is free — you just need to know whose system to ask. The container number itself tells you.
One thing this page is not: a tracker. We do not operate tracking infrastructure; this is a how-to for using the carriers’ own tools, which are the authoritative source anyway.
How do you track a container by number?
1. Read the number. Four letters and seven digits, stencilled on the doors and both sides: e.g. MSKU 123456-7. The first three letters are the owner code, the fourth is always U for freight containers, and the final digit is a check digit computed from the rest. The full format is defined by ISO 6346 — see ISO container standards.
2. Identify the operator. MSKU/MRKU → Maersk; MSCU/MEDU → MSC; CMAU/CGMU → CMA CGM; HLCU/HLXU → Hapag-Lloyd; OOLU → OOCL; EVRU/EISU → Evergreen; COSU → COSCO. The BIC registry resolves any prefix.
3. Look it up. Paste the number into that carrier’s tracking page, or a multi-carrier tracker that queries them all. Port terminal websites also show gate and yard status for boxes on their ground.
Container number vs booking vs B/L
Three different identifiers get confused constantly. The container number identifies the physical box and stays with it for life. The booking number identifies your reservation with the carrier — one booking can cover many containers. The bill of lading (B/L) number identifies the shipment contract and its cargo. Carrier trackers usually accept all three; container numbers show one box’s moves, while 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.
What tracking shows — and what it doesn’t
A working track returns the event chain: empty pickup, gate-in at origin terminal, load on vessel (with vessel name and voyage), transshipment moves, discharge, gate-out, empty return. Between ports you see the vessel’s AIS position and the carrier’s ETA — which shifts with weather and port congestion, so treat any date more than a week out as an estimate. 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.
Why does container tracking show “no data”?
The most common reason: the box is no longer in shipping. Containers sold for storage or conversion keep their numbers painted on, but no carrier system tracks them — a number that resolves to nothing usually means a retired box. Other causes: the container is between systems (returned empty, not yet re-leased), the feed is delayed (terminal events can lag 6–24 hours), the prefix belongs to a small operator without public tracking, or the number was simply misread — check the final digit against the check-digit rule, since a single wrong character fails validation.
Frequently asked questions
How do I track a container by container number?
Read the 11-character number from the door (e.g. MSKU 123456-7), identify the carrier from the letter prefix (MSKU = Maersk, MSCU = MSC, CMAU = CMA CGM), and enter it on that carrier’s tracking page. You get vessel, ETA and terminal moves free of charge.
Can I track someone else’s container?
Yes — carrier tracking is public by design. Anyone with the container number can see its moves, because consignees, truckers, terminals and customs all need the same data without accounts or authorisation. No cargo details are shown, only the box’s movements.
Why does container tracking show nothing?
Usually the box has left the shipping network — containers sold into storage keep their painted numbers but are no longer tracked. Otherwise: feed delays of up to 24 hours, a box idle between leases, a small carrier without public tracking, or a misread number failing its check digit.
What is the difference between a container number and a B/L number?
The container number identifies the physical box for life; the bill of lading number identifies one shipment’s contract, and a booking number one reservation — either may cover several containers. Trackers accept all three, but only the container number follows a specific box.
What do the letters in a container number mean?
The first three letters are the owner’s BIC code (MSK = Maersk, MSC = MSC, CMA = CMA CGM); the fourth is the equipment category — U for all freight containers. The seven digits that follow include a final check digit that validates the whole number.