Very few line items surprise importers as reliably as container fees. The freight rate was quoted, agreed, and budgeted. Then a container sits four days too long and an invoice arrives that is a meaningful fraction of the original shipping cost.
Demurrage, detention, and per diem are three separate charges that people routinely use interchangeably. They are not the same, they are billed by different parties, and the actions that prevent each one are different. Here is the clean version.
The three clocks
Demurrage: the container is still inside the terminal
Demurrage starts when a loaded import container has been discharged from the vessel and made available for pickup, and the free time granted for it expires while it is still sitting in the terminal yard.
It is charged by the terminal or the ocean carrier, and it accrues per container per day. Demurrage is fundamentally a storage fee — the terminal is telling you that its yard is not a warehouse.
Detention: the container is outside the terminal
Detention starts once you have pulled the container out of the gate and you keep the carrier’s equipment longer than the free time allows before returning the empty.
Same concept, opposite side of the fence. Demurrage is “your box is in our yard.” Detention is “our box is in your yard.”
Per diem: the daily rate on the equipment itself
Per diem is the daily charge for use of the container (and often the chassis) beyond the allowed period. In practice, many carriers use “detention” and “per diem” to mean the same charge on import moves. The distinction that matters operationally is that chassis per diem is frequently billed separately by the chassis pool, so returning a container without returning the chassis can leave a clock running you did not know about.
What triggers each one in real life
Nearly every demurrage bill traces back to one of a short list of causes:
- Customs or FDA holds — the container is available but legally cannot move.
- Unpaid or unreleased freight — the ocean carrier has not issued release.
- No trucking capacity booked — the box was available and nobody was scheduled to get it.
- No terminal appointment — capacity existed but the appointment system had nothing open.
- Terminal congestion — gate delays, vessel bunching, or labor disruptions.
Detention and per diem come from a different list:
- No receiving appointment at the warehouse or the appointment is days out.
- Slow unloading — the container is live-unloaded but the dock is backed up.
- Nowhere to stage the box — the consignee has no yard space, so the container sits on a truck or on the street.
- Empty return restrictions — the terminal is not accepting that container type that day.
Notice how many of these are scheduling problems rather than freight problems. That is the key insight: container fees are usually a symptom of a planning gap, not of anything going wrong with the cargo.
How to keep the clocks from running
Know your last free day before the vessel arrives
Ask for the last free day for demurrage and the last free day for detention at booking, not at arrival. Put both on a calendar with a reminder two days out. This single habit prevents more container charges than anything else on this list.
Clear customs before discharge, not after
File early and confirm your broker has everything. A hold that lands after discharge burns free time you cannot get back.
Book drayage in advance, not on availability
Appointment slots at PortMiami and Port Everglades are finite. Booking a drayage move the day the container becomes available means competing with everyone else who did the same thing. Book against the estimated availability date and adjust.
Decide up front: live unload, drop and pick, or transload
These three options have very different fee profiles.
- Live unload — the truck waits while you unload. Cheapest if your dock is fast, expensive if it is not, because driver waiting time is billable.
- Drop and pick — the container is dropped at your facility and collected later. Frees the driver but keeps the detention clock running.
- Transload — the container is stripped at a container freight station and the cargo continues on domestic equipment. The empty goes straight back, stopping detention and per diem early, and the freight moves onward as LTL or truckload on your schedule.
Transloading is often the right answer when your own dock is the bottleneck. It converts an ocean-equipment problem into a domestic freight problem, and domestic freight is far easier to schedule around.
Have somewhere to put the box
If your facility cannot take the container today, staging it in yard storage is generally cheaper than accruing demurrage in a terminal — and it gets the empty returnable sooner. Compare the daily numbers rather than assuming.
Confirm the empty return actually happened
Get the interchange receipt. Confirm the chassis was returned and closed out. Charges that continue after a return are common and almost always resolvable with documentation — if you have it.
Disputing a charge
Not every fee is valid. If the delay was caused by circumstances outside your control — terminal closure, no available appointments, an equipment shortage, a hold you did not cause — you may have grounds to dispute.
What wins disputes is a timeline: availability notification, appointment attempts with timestamps, gate transactions, hold notices, and the empty return receipt. What loses disputes is a phone call three weeks later with no records. Keep the paper from day one and file promptly.
The short version
Demurrage is inside the gate. Detention and per diem are outside it. All three are clocks that start whether or not anyone is watching them, and all three are prevented by scheduling rather than negotiating.
If you are moving import containers through South Florida and want the drayage, transload, and storage side handled by one operator, get in touch — coordinating those three under one roof is usually where the free-time savings come from.
Frequently asked questions
What is the difference between demurrage and detention?
Demurrage is charged for a container sitting inside the terminal past its free time. Detention is charged for a container held outside the terminal past its free time. Same idea, different side of the gate.
How much free time do I get?
Free time is set by the ocean carrier and the terminal and typically runs a few days for demurrage and a few days for detention. It varies by carrier, service contract, and port, so confirm it per booking rather than assuming.
Can demurrage charges be disputed?
Sometimes. If the delay was caused by terminal congestion, an unavailable appointment, or a customs hold outside your control, document the timeline and file a dispute. Clean records are what make those cases winnable.