You already know what demurrage and detention are. The harder question is what to do when you get billed for them and you do not believe you should have been. Most shippers pay anyway, because disputing feels like a losing fight against a large carrier with a form letter.
It is not a losing fight, but it is a documentation fight. Disputes are won by people who assembled the record before they needed it. Here is how to build that record and how to structure the dispute itself.
First, know which charge you are actually disputing
Precision matters here, because the counterparty is different for each:
- Demurrage — the container is still at the terminal past free time. Billed by the ocean carrier or terminal.
- Detention (per diem) — you have the container out of the terminal past free time. Billed by the ocean carrier.
- Driver detention — you held the trucker’s driver at your facility beyond free time. Billed by the motor carrier.
These are three different charges with three different clocks and three different people to argue with. If your dispute letter confuses them, it will be dismissed on that basis alone. If you need the underlying definitions, start with our demurrage vs. detention explainer.
The grounds that actually work
Not every dispute is winnable. These are the arguments that hold up.
1. The container was not actually retrievable
The strongest argument in the category. If free time was running while the container was physically unavailable — not yet discharged, not yet released, under a customs or terminal hold you did not cause, or buried in a stack — then charging you for that period is charging you for something you could not have prevented. Document the release date and the availability date separately, because they are frequently not the same day.
2. No appointment was available
If the terminal requires appointments and none existed within the free-time window, you were structurally prevented from performing. Screenshots of the appointment system showing no availability, taken on the relevant dates, are the evidence. This is why you take them contemporaneously — you cannot recreate them later.
3. The terminal was closed or not accepting returns
Empty returns are frequently restricted by carrier, by container type, or by day. If the terminal would not accept your empty on the days you were being charged per diem, that is a documentable defense.
4. The billing is arithmetically wrong
Unglamorous and extremely common. Wrong start date, weekends and holidays counted that should not have been, free days miscounted, or the same day billed on two invoices. Check the math before you build a legal argument — a good share of disputes resolve here.
5. The charge lacks required detail
An invoice that does not identify the container, the specific dates charged, the applicable free time, and the rate is not an invoice you can verify. Requesting complete detail is a legitimate first move and frequently produces a correction without any further argument.
Grounds that generally do not work
Be realistic. These arguments rarely land:
- Your own facility was backed up or short-staffed.
- Your trucker could not get a chassis or was capacity-constrained.
- You did not know the free time had started.
- The charge feels unreasonably large.
The consistent principle is that the charge is defensible when the delay was within your control, and challengeable when it was not.
Build the file before you write the letter
Assemble, per container:
- Bill of lading and arrival notice
- Vessel discharge date
- Customs release date and carrier release date
- Stated free time and calculated last free day
- Container availability confirmation
- Appointment system screenshots for the relevant dates
- Out-gate and in-gate timestamps
- Any hold notices and their resolution dates
- The invoice itself and any prior related invoices
This is the entire dispute. A well-organized file wins more often than a well-argued letter with weak documentation.
How to write the dispute
Be specific and narrow. Dispute identified days on an identified container, not the invoice in general. “We dispute four days of per diem on container XXXU1234567, covering the period the terminal was not accepting empty returns for this equipment type” beats “these charges are excessive.”
State the ground plainly. One sentence naming why the charge should not apply.
Attach the evidence, labeled. Reference each exhibit in the text.
Calculate what you believe is owed. Conceding the days that are legitimately chargeable makes the disputed days far more credible. A dispute that concedes nothing reads as a negotiating posture; a dispute that concedes most of the invoice and challenges four specific days reads as an audit.
Ask for a specific action and a date. A revised invoice, by a stated deadline.
Keep it short. One page plus exhibits. The person reading it is processing a queue.
Timing and escalation
File quickly. Dispute windows exist, they vary by carrier, and they are usually shorter than you expect. A dispute raised within days of the invoice carries more weight than the identical dispute raised in ninety.
If the first response is a form denial, escalate once — to a named person, with the same file and a short cover note explaining what the initial response did not address. Many disputes are denied at first pass by process and resolved at second pass by a human.
US ocean carrier billing practices for demurrage and detention are subject to Federal Maritime Commission regulation, and the specifics of what carriers must include on invoices and how disputes must be handled have been actively litigated and revised in recent years. If a charge is significant and the carrier will not engage, confirm the current rules and available remedies with the FMC or transportation counsel rather than relying on the state of the rules as of any particular article.
Prevent more than you dispute
Disputes are recovery. The higher-value work is upstream:
- Track last free day for every container as a scheduled event, not as something someone remembers.
- Book terminal appointments the moment the container is available, not the day you want it.
- Ask for extended free time during contract negotiation. It is negotiable more often than shippers assume, and it costs nothing to request.
- Consider a pre-pull when free time is about to expire and your dock is not ready — a pre-pull fee is almost always cheaper than accumulating demurrage.
- Track per-diem and demurrage exposure by lane so you can see which routings are structurally expensive.
Related reading
- Demurrage vs. Detention: The Difference and How to Avoid Both
- How to Cut Drayage Costs in 2026
- How to Audit a Drayage Invoice: Every Charge Explained
The Freight Guru podcast covers the operational reality behind charges like these. Subscribe here.
Working with a drayage partner who tracks free time for you removes most of this problem. Go Freight handles port drayage in the Miami market.
