When you import products in containers and need some time for customs clearance or local transportation arrangements, you will eventually encounter two unpleasant words: demurrage and detention.

For many new importers, these charges come as a surprise. They are usually not included in the freight quote, yet they can easily add hundreds or even thousands of dollars to a shipment.

The frustrating part is that most people only learn the difference after they receive the invoice. Often, exporters or freight forwarders simply mention the ‘total free time’ for a shipment without clearly separating demurrage and detention.

In reality, demurrage and detention are simple concepts. However, being unaware of them could cost you $$$ in logistics.

What is Demurrage?

Demurrage occurs when a container remains at the port terminal longer than the free time allowed by the shipping line.

Once the container is discharged from the vessel, the terminal begins counting the free days. If the importer does not pick up the container within that period, demurrage charges begin to apply.

Typical situations that cause demurrage include:

  • Surprisingly, sometimes the problem is simply not being aware that the container has already arrived. If you have multiple containers arriving at the same time, one shipment may be overlooked and continue accumulating charges at the terminal.
  • Missing documents or issues with customs procedures (such as product registration or import permits)
  • In the case of a surrender B/L shipment, the remaining balance payment to the exporter has not yet been made, and the B/L has not been surrendered, making customs clearance impossible.
  • Delays in arranging trucking
  • Port congestion
  • Intentional: your warehouse has no available space, so the container remains at the container yard.

For example, if a shipping line provides five free days and the container is picked up on day eight, the importer will be charged demurrage for three days.
During this period, the container is still inside the port terminal.


What is Detention?

Detention occurs after the container leaves the port.

Once the container is picked up from the terminal, the importer is given a certain number of free days to return the empty container to the shipping line’s designated depot. If the container is returned late, detention charges apply.

Common causes of detention include:

  • Slow unloading at the warehouse
  • Limited warehouse space, forcing the consignee to temporarily store goods inside the container
  • Poor coordination with trucking companies
  • Long distances between the warehouse and the container depot

In simple terms, the shipping line charges detention because their container is being used outside the port for longer than the allowed time.


The Key Difference
The easiest way to understand the difference is:
Demurrage = the container stays inside the port too long
Detention = the container stays outside the port too long
Both charges exist because containers are assets owned by shipping lines. When containers are tied up for too long, they cannot be used for other shipments.

NOTE: For the same reason that containers are assets owned by shipping lines – shipping lines may also charge for container damages upon return unless the consignee can prove the damage already existed at the time of pickup. Normally, this is verified through the Equipment Interchange Receipt (EIR).
In some cases, shipping lines may even charge ‘cleaning fees’ if unwanted labels or stickers are left on the container.


Why These Charges Become Expensive

Many importers underestimate how quickly these costs can accumulate.
Demurrage and detention are usually charged on a daily basis, meaning the cost increases every single day. The rates may also escalate after several days.
!! The worst scenario occurs when the importer is not even aware that the container has already arrived at the port. Although shipping lines usually send an arrival notice in advance, this is not mandatory, and sometimes the notice may be delayed or misdirected.
In such situations, the bill can grow surprisingly fast.


How Experienced Importers Avoid These Costs

Companies that regularly manage logistics usually follow a few simple rules.

  • Pay attention to ETD and ETA: Always monitor the vessel schedule and expected arrival date at your destination port. If you know the vessel name, you can track its location using online services such as Tradlinx / MarineTraffic / VesselFinder websites. You can also contact the shipping line directly for updated schedules.
  • Know the free time: Free time policies may vary depending on the shipping line, port, and the nature of the products. Always confirm the number of free days granted for demurrage and detention. Although the terminology may differ, the underlying concepts are the same. For example, the CY free period indicated below effectively refers to the demurrage free time.
  • Prepare documents early: Whenever possible, customs documentation should be prepared before the vessel arrives. Please ensure that all required documents and permits are ready in advance for customs clearance.
  • Confirm trucking in advance: Waiting until the container arrives before arranging transportation is risky and may cause unnecessary delays.
  • Coordinate with your forwarder: Clear communication with your freight forwarder can prevent small delays from turning into expensive problems.
  • Appeal if desperate: If there are valid reasons for a delay—such as customs inspections or documentation issues—you may try to appeal to the shipping line for a discount on the charges. This is somewhat similar to receiving a speeding ticket: it is not common for the charge to be reduced, but with a reasonable explanation, it is sometimes possible. In one of my cases, a shipping line granted a partial discount because the delay was clearly beyond the importer’s control.
  • Another option is to ask the exporter—who originally booked the shipment—to request an extension of free time or negotiate a discount with the shipping line at the origin side.


Personal Experience

In one case involving a general cargo shipment (meaning NOT hazardous, explosive, flammable, toxic, or classified as dangerous goods), approximately USD 1,000 in charges were incurred for two FCL containers that remained in the container yard for about one month beyond the free time in 2025.
Situations like this highlight how quickly demurrage costs can accumulate when containers remain uncleared at the terminal.

“Wouldn’t the shipping line send an arrival notice?”
Usually yes. Shipping lines typically send arrival notices by email or fax because they also prefer not to keep uncleared containers at the terminal for long.
However, even if an arrival notice is not received due to communication issues—such as an incorrect email address or a missed message—the responsibility still remains with the importer to track the shipment and clear the cargo on time.


Frequently Asked Questions


Q. How many free days are usually given?
Typically, shipping lines provide around 4–7 days of demurrage free time and another 4-7 days of detention free time, depending on the port, shipping line, and market conditions. Sometimes exporters only mention the total free time, for example “14 days free time”, However, you should always confirm how the free time is divided between demurrage and detention. This does not mean you can keep the container at the port for 13 days and clear customs on the last day. Demurrage charges would still apply in that case.

Q. If you do not clear your container out, do shipping lines just store them in the Container Yard forever?

No. Shipping lines will not store containers in the Container Yard indefinitely. Once the free time expires, demurrage charges begin to accrue on a daily basis.

If the cargo remains uncleared for an extended period, the shipping line will typically contact the importer or consignee to determine the situation. If the cargo is still not cleared, it may eventually be treated as abandoned cargo and become subject to customs procedures such as auction or disposal, depending on local regulations.

Q. Special cargo considerations!

For special or dangerous cargo, such as highly flammable materials, free time may be very limited or not granted at all, depending on port safety regulations. In such cases, the cargo must usually be cleared immediately after discharge, or special handling arrangements may be required.

In one instance, a shipment of high-pressure gas was not cleared in time after the vessel arrived. Because it was classified as dangerous cargo requiring prior approval from the port authority, the container was not discharged at the terminal and remained on board. As a result, the vessel eventually departed with the cargo still on board.


Final Thoughts


Demurrage and detention are not penalties. They are simply part of how container logistics works.
However, failing to plan for them can turn an ordinary shipment into a very expensive one.
For anyone involved in importing or exporting, understanding these two terms is not optional. It is basic logistics knowledge that can save thousands of dollars.