A container terminal is the fenced part of a port where boxes change hands between ships, trucks and trains. It works as three linked systems: the berth, where quay cranes load and discharge vessels; the yard, where containers are stacked while they wait; and the gate, where trucks drop off and collect them. Your box only leaves when all three have done their part and every hold on it is cleared. The key takeaway for shippers: "discharged" does not mean "available", and the free-time clock usually starts before you can actually collect. This guide walks through each stage and the vocabulary you see in container tracking, so you can tell where a delay really sits.
The three zones of a container terminal
Every terminal has the same basic layout. Ships tie up at the quay, where ship-to-shore (STS) cranes lift boxes on and off. Behind it is the yard, divided into blocks of stacked boxes worked by gantry cranes, straddle carriers or reach stackers, with separate areas for empties, reefers and dangerous goods. At the landward edge are the truck gate and often a rail siding. Stacking is why a terminal cannot simply hand over one box on request: retrieving a container buried under four others means moving those four first.
Terminal operating systems
A terminal operating system (TOS), such as the widely used Navis N4, tracks every container's position and plans every move. It is the source of truth behind the statuses on terminal websites, carrier portals and tracking tools. When two sources disagree, the terminal's own record is usually the one that decides whether a truck gets the box.
The berth: vessel planning, stowage and quay cranes
Before a ship arrives, the carrier's stowage planners decide where each container goes on board, balancing weight, stability, port rotation, dangerous goods segregation and reefer plug positions. The terminal turns that into a crane work plan. The plans travel as standard electronic messages, notably BAPLIE, the bay plan message maintained by the industry group SMDG, which tells the next terminal what sits in each slot. This is why late changes hurt: a box that arrives after the plan is fixed may be left behind even if there is physical space.
For shippers, the berth produces two common delays:
- Berth windows slip. A ship that misses its berth window may wait at anchor for the next free berth. That does not show as a terminal delay on your tracking; the ETA simply moves.
- Your box is not discharged first. Discharge follows the crane plan, not urgency, so two containers from the same ship can become available at different times.
On the export side, the risk is being rolled: the box is in the yard but does not make the ship. Our guide to rolled cargo prevention covers why that happens and how to reduce the odds.
The yard: stacking, dwell time and reefer plugs
The yard is a buffer. Imports wait there for customs, carrier and terminal clearance, and for a truck or train. Exports wait there for their vessel. The time a box spends there is its dwell time. When dwell rises, stacks get higher, re-handling increases and every truck appointment takes longer to serve. That is the mechanism behind much port congestion: a yard that fills up because boxes are not leaving.
Terminals discourage long dwell through free time and storage or demurrage charges. Free time is the number of days a container may sit in the terminal before charges start. Depending on the port, the carrier bills demurrage under its tariff, the terminal bills storage, or both. Free time varies widely and can be negotiated in a service contract, so read your own contract and the terminal tariff rather than relying on a typical figure.
The last free day
The last free day (LFD) is the final day you can collect an import container without incurring demurrage or storage. Charges generally start the day after. LFD is set by when free time began, which is usually tied to discharge or availability, not to when your customs broker filed or when your trucker had a slot. In the United States, carriers and marine terminal operators covered by the Federal Maritime Commission's billing rule must now show on a demurrage or detention invoice the allowed free time, the start and end dates of free time and, for imports, the container availability date (46 CFR 541.6). Those fields are exactly what you need to check whether the clock was started fairly. Our guide to FMC demurrage and detention billing rules explains how to dispute an invoice.
Once the box leaves, a different clock usually starts: detention (or per diem) for keeping the carrier's equipment outside until the empty is returned. See container damage, detention and per diem for who pays which.
Reefers
Refrigerated containers go to a dedicated area with plug points, and terminals typically charge for power and monitoring, often per day, on top of storage. Plug capacity is limited, so a reefer that misses its sailing or sits uncollected keeps occupying a scarce plug and accruing charges.
The gate: appointments, gate-in, gate-out and the EIR
Appointment systems
Many busy terminals require trucks to book a time slot before arriving. The Port of Felixstowe, for example, runs a Vehicle Booking System in which hauliers book a slot to deliver or collect a container. The catch: a container can be available and still not collectable today because no slot is free. Plan around the last free day by counting back from appointment availability, not from the availability date.
Gate-in for exports
Exports are accepted only inside a receiving window, from the earliest receiving date to the cargo cut-off. The trucker needs a valid booking reference, and the box needs a verified gross mass (VGM) on file, because under the SOLAS convention a packed container should not be loaded without one. See container weight limits, payload and VGM. Arriving before the window opens can mean the box is refused; arriving after cut-off can mean it is accepted but rolled.
Gate-out for imports
For imports, the trucker presents a pickup or release reference, the terminal checks that every hold has been cleared, and the box is brought to the truck. When it leaves, the tracking event becomes "out-gated" or "gate-out full", demurrage stops, and detention typically starts.
The Equipment Interchange Receipt
Each time the container changes hands at the gate, the terminal records an Equipment Interchange Receipt (EIR), sometimes called an interchange receipt or gate ticket. In North America the industry contract governing these handovers is the Uniform Intermodal Interchange and Facilities Access Agreement (UIIA), which defines the EIR as the document confirming the interchange of equipment between parties, with the physical condition recorded on the receipt or through recorded images. It is your evidence in two common disputes: whether damage existed at pickup, and when an empty was actually returned, so keep every one. The empty return leg has its own problems, covered in empty container return and avoiding detention.
Holds: why an available box may not be releasable
An import container usually needs several independent clearances before it can leave. Each appears as a hold in the terminal system, and the box is only releasable when all are lifted.
- Customs hold. The customs authority has not released the shipment, either because the entry is not filed or accepted, or because the box has been selected for examination.
- Other government agency hold. Agencies responsible for food, plants, animals or product safety can place their own holds, separately from customs.
- Freight or carrier hold. The carrier has not released the cargo, typically because freight or local charges are unpaid or the original bill of lading has not been surrendered.
- Terminal or fee hold. Terminal charges or local fees are outstanding. At Los Angeles and Long Beach, for example, containers commonly show a hold until the PierPass Traffic Mitigation Fee is paid.
Customs exams and free time
When customs selects a container, the exam can range from a non-intrusive scan (an X-ray or gamma image, usually without opening the box) to a physical exam where the container is unloaded. In the United States, intensive exams usually take place at a Centralized Examination Station (CES), a privately operated facility defined in 19 CFR 118.1. The importer generally bears the cost of preparing merchandise for examination (19 CFR 151.6), and when cargo is sent to a CES the importer or its agent normally pays for the bonded transfer and the CES's fees. CBP does not invoice the exam itself, but trucking, devanning, storage and demurrage can all accrue while it runs.
A common misconception is that free time stops while customs holds the box. Usually it does not. In the US, the FMC's interpretive rule on demurrage and detention (46 CFR 545.5) says the Commission may consider government inspections when judging whether charges were reasonable, which is grounds for asking for mitigation, not an automatic pause. If an exam is going to push you past the last free day, raise it with the carrier or terminal early, in writing, and keep the exam notifications.
Tracking vocabulary: what each status actually means
Exact wording varies between carriers, terminals and tracking tools, but most statuses map to the stages below. Our guide to container tracking covers which number to track with.
| Status you see | What has happened | What it does not mean |
|---|---|---|
| Arrived / vessel at berth | The ship is alongside and cargo work may have started. | Your box has been discharged. |
| Discharged | The box is off the ship and in the terminal yard. | It is free to collect. Holds may still apply. |
| Available | The terminal can deliver the box; often free time is now running. | Every hold is cleared, or a truck slot exists. |
| Customs released | The customs authority has released the shipment. | The carrier has released it, or other agencies have. |
| Freight released | The carrier has released the cargo (charges paid, bill of lading surrendered). | Customs has released it. |
| Hold / on hold | At least one clearance is outstanding. | Who placed it. Ask which hold type it is. |
| Out-gated / gate-out full | The loaded box has left the terminal by truck. | Delivered to the consignee. |
| Empty returned / gate-in empty | The empty has been returned and interchanged. | Detention has been settled. |
Terminal handling charges: what they are and who pays
Terminal handling charges (THC) pay for moving the container between the ship and the terminal stack and through the terminal. They are charged at both ends: origin THC (OTHC) at the port of loading and destination THC (DTHC) at the port of discharge. They are usually quoted per container as a separate line from ocean freight.
Who pays THC between buyer and seller is decided by your sales contract and the Incoterms rule it uses. Incoterms do not name THC as such; they divide costs at the delivery point. Broadly, under FOB the seller bears costs until the goods are on board at origin, so origin THC usually falls to the seller and destination THC to the buyer. Under CFR and CIF, the seller pays freight to the destination port, but unloading costs there typically fall on the buyer unless the seller's contract of carriage already included them. Because practice varies, state who pays each THC in the sales contract. Our Incoterms 2020 guide covers the full list.
Checklist: before your box reaches the terminal
- Customs entry filed early enough to be processed before discharge, with any agency permits on hand.
- Freight and local charges paid, and the original bill of lading surrendered or a waybill or telex release in place.
- Terminal-specific fees paid in advance where the port requires it.
- Free time, last free day, detention allowance and the empty return depot confirmed in writing.
- For exports: receiving window, cargo cut-off, documentation cut-off and VGM deadline confirmed.
What to do next
- For your next import, ask your forwarder or carrier for the expected discharge date, the free time and the last free day before the ship arrives, not after.
- When tracking shows "available", check which holds remain rather than assuming the box is collectable.
- Book drayage around appointment availability and the last free day. If the box will go to an exam, warn your trucker and budget for exam costs; our US drayage and chassis guide explains the trucking side.
- Keep every EIR and dated hold notice. On a US invoice, compare the stated availability date and free-time dates against them before you pay.
If you need a forwarder or customs broker who handles a particular port, more than 29,300 logistics companies are searchable by country and service in the CargoLinked directory. To get quotes on a specific shipment, the public requests board lists freight that shippers have posted for forwarders to quote on directly.
This guide is general information, not legal, customs or financial advice. Terminal rules, free time, fees and customs procedures vary by port and change over time; confirm the current position with the carrier, the terminal operator, the customs authority or a licensed customs broker before relying on it.
