The number you’re holding decides which website can help you
Most tracking problems start before anyone opens a tracking page. You have a reference on an email from your supplier, you paste it somewhere, and you get a red error or a blank screen. That usually isn’t broken tracking. It’s the wrong number in the wrong system.
Each mode has its own reference and they are not interchangeable.
Ocean: bill of lading number or container number
Two references work for container tracking on a carrier’s site: the bill of lading number and the container number. Carrier portals and third-party aggregator sites accept both.
Container numbers follow ISO 6346, so they have a shape you can check by eye: four letters, then seven digits. The first three letters are the owner code, the fourth is almost always U for a freight container, and the last digit is a check digit. The pattern looks like MSCU1234567. That is the format, not a live box. If what you were sent doesn’t match that pattern, it isn’t a container number, and no amount of retyping will make a carrier site accept it.
The bill of lading number sits on the B/L itself. Here is the part that catches importers out: if your forwarder issued you a house bill of lading, the shipping line’s website generally won’t recognise it, because the line only knows its own master bill. Ask your forwarder for the master B/L number or the container number if you want to watch the vessel leg yourself. Everything else on your file, the pickup, the documents, the delivery, lives in the forwarder’s system, not the carrier’s.
Air: the air waybill number
An AWB is 11 digits, and the first three are the airline prefix code. The number itself tells you whose cargo portal to open. That’s all you need for air waybill tracking on the airline’s own site, and your forwarder’s system will show the same events with the trucking and customs legs attached.
Express: each carrier’s own number, each carrier’s own portal
DHL, FedEx and UPS each issue their own tracking number and each runs its own tracking page. An express number won’t resolve on an ocean carrier’s site, and vice versa.
What each ocean milestone actually means for your cargo
The typical sequence runs like this. What matters isn’t the wording, which varies by carrier, but what has physically happened and who is holding your box at that moment.
- Booking confirmed. Space is reserved. Nothing physical has happened yet. Your cargo may still be at the factory.
- Cargo received at CY/CFS. The box or the loose cargo is now in terminal or warehouse custody. Cutoffs matter from here: miss the documentation or gate-in cutoff and you roll to the next vessel, regardless of what the booking says.
- Loaded on vessel. Physically on board. This is the first event most importers actually trust.
- Vessel departed (ATD). Actual departure. Your real transit clock starts at this event, not at the booking date, which is why estimated ocean shipping times from China should always be counted from ATD.
- In transit / transshipment. The quietest phase and the one that generates the most panic. On a direct service you may see nothing for a long stretch, which is normal. On a service that transships, your container is discharged at an intermediate port and waits for a connecting vessel, so understanding your shipping routes from China before booking tells you whether silence is expected or a problem.
- Vessel arrived (ATA). The ship is at the destination port. Your container is still on it.
- Discharged. The container is off the ship and sitting on the terminal. Note this one. This is usually where free time and the money clock enter the picture.
- Customs release. Customs is finished with the entry. It does not mean the box can move, because terminal holds and unpaid charges are separate from customs.
- Available for pickup. Everything that could hold the container has cleared and the terminal will release it to a trucker.
- Out for delivery, then proof of delivery. On the road, then signed for.
Air cargo status codes, decoded
Air uses short IATA codes, and once you know six of them you can read an air waybill history without asking anyone.
- RCS — received from shipper. Cargo is in the airline’s hands at origin. It has not flown.
- MAN — manifested. Assigned to a specific flight.
- DEP — departed on that flight.
- ARR — arrived at the airport.
- RCF — received from flight. Offloaded and in the airline’s import warehouse.
- NFD — consignee notified. The arrival notice went out.
- DLV — delivered.
The gap that eats time is between RCF and NFD. The cargo has landed but hasn’t been broken down from its ULD, checked in to the warehouse and made available. Cargo can sit in that gap while your tracking page shows nothing new.
ETD and ETA are guesses. ATD and ATA are facts.
Estimated departure and estimated arrival are planning figures and they move. Actual departure and actual arrival are events that happened. Schedules shift routinely, and transshipment is where they shift most, because your cargo now depends on two vessels lining up instead of one.
Practical consequence: never promise a customer a delivery date built on an ETA. Build it on ATD plus a realistic transit, and rebuild it the moment a connection changes. If a term on your tracking page or your B/L isn’t familiar, our freight glossary covers the vocabulary carriers use without explaining.
Triage: your tracking looks stuck, so what’s actually happening?
This is the table to keep. Find the symptom, get the likely cause, then ask the party who can actually see it. Asking the wrong party is why people wait three days for “we’ll check with the line.”
| What tracking shows | Most likely cause | Who to ask | What to ask for |
|---|---|---|---|
| “In transit” with no new event for days | Vessel at sea, or waiting for a connecting vessel at a transshipment port | Forwarder (carrier for vessel events) | Current vessel and voyage, connecting vessel, revised ETA at final port |
| Arrived at a port that isn’t yours, then silence | Transshipment; container may have been rolled to a later connection | Forwarder | Confirmation the box was loaded on the connection, or the next confirmed sailing |
| Vessel arrived, no discharge event | Berth wait or terminal congestion | Forwarder or carrier | Berthing and discharge schedule, and your last free day once discharged |
| Discharged, but never “available for pickup” | A hold: customs, terminal, or unpaid freight/charges | Forwarder first, then customs broker | Which hold is on the container, what releases it, whether free time is running |
| Entry filed, no customs release | Document or classification query, or an exam | Customs broker | Exactly what customs asked for, the deadline, and if it’s an exam, which type and where |
| AWB shows RCF, no NFD | Landed but not yet broken down and checked into the import warehouse | Forwarder or the airline’s handling agent | Warehouse location, breakdown status, when it can be collected |
| Number returns “not found” | House B/L pasted into a carrier site, wrong mode, or too early for events | Forwarder | The master B/L number and the container number |
| Shows delivered, nothing arrived | Wrong stop, wrong door, or an event keyed early | Forwarder | POD copy with signature, timestamp and delivery address |
Who can actually answer what
Four different parties, four different windows, and none of them sees the whole picture.
The ocean carrier knows vessel and container events. Loading, sailing, arrival, discharge. It doesn’t know whether your supplier’s documents were correct or where your trucker is.
The freight forwarder holds the end-to-end file: pickup at the factory, documents, the vessel leg, arrival handling, delivery. When you don’t know who to ask, this is the default, because the forwarder can see enough to route your question to the right party.
The customs broker knows the entry status and what, if anything, customs has queried. If the delay is a classification question or an exam, this is the only party who can give you a straight answer, and understanding the customs clearance process ahead of time makes those conversations much shorter.
CBP does not provide public real-time clearance status to parties who aren’t the filer. If someone tells you to “check with customs directly,” they’re passing the parcel. Go to your broker.
The milestones where money starts
This is why reading tracking properly is worth your time. Two charges catch importers who watch tracking passively instead of acting on it.
Demurrage accrues on a full container sitting inside the terminal past its free time. Detention accrues when you’ve taken the container out and are holding the box or chassis past free time before returning it.
How much free time you get varies by carrier, by trade lane and by what’s in your contract, so there is no universal number worth quoting. Ask for yours at booking, in writing, and ask again when the container is discharged, because the last free day is the date you actually need on your calendar.
The operational point: by the time your tracking says “available for pickup,” the clock may already be several days in. If you wait for a warning, you’re paying. Have your delivery order, your customs entry and your trucker lined up before discharge, not after.
How to ask so you get an answer the same day
Vague questions get vague answers. Send the reference number, the mode, the exact status wording you’re seeing with its date, and the specific thing you need: a revised ETA, a hold type, a last free day. One message with all four beats five rounds of back and forth.
And if you’re tired of chasing a status nobody will explain, that’s a forwarding problem, not a tracking problem. Tell us your lane, your commodity and your timeline and get a freight quote from a team that sends the milestone updates before you have to ask for them.