Whose clock is actually running on your container?

Three charges people call one thing

Carrier demurrage is what your ocean carrier bills when its container stays on the marine terminal past the free time the carrier gave you. This is almost always the invoice that reaches an importer.

Detention is the carrier's charge for keeping its equipment too long once it is off the terminal, typically sitting at your own warehouse while you unload. Same billing party, different clock, different trigger. The Federal Maritime Commission draws the line exactly there: demurrage relates to use of terminal space, detention to extended use of the carrier's equipment.

Port wharf demurrage and terminal storage are the port's own charges on cargo occupying port property. Different party, different tariff, and here is the part that surprises people: at both South Florida ports, these are billed to the steamship line or its agent, not to you. Port Everglades says so in the tariff item itself.

So when someone says the port is charging you demurrage, they are usually describing a carrier charge. It matters because you dispute the two in completely different places.

What the ports' own tariffs say

PortMiami's tariff, effective October 1, 2025, gives 10 days of free time including weekends and holidays. After that, wharf demurrage runs at $1.54 per ton for each of the first seven days and $2.42 per ton from the eighth day on, with a $100 minimum invoice. Terminal storage on a loaded or empty 20 foot container runs in monthly tiers of $15.12, then $51.00, then $120.89, with an $85 minimum.

Port Everglades Tariff No. 12, also effective October 1, 2025, gives 12 days free time on inbound containers and 15 on outbound. Its wharf demurrage is $11.38 per container per calendar day, and open ground storage is $5.84 per container per day, with a $59.67 minimum invoice. After six approved storage periods, the charges revert to wharf demurrage rates.

Notice that the two ports do not even price the same way. Miami charges by the ton, Everglades by the container. Comparing them without reading both tariffs produces nonsense.

The rule that used to protect you, and does not anymore

This part matters and most content on the subject is now out of date, so read the dates carefully.

In February 2024 the Federal Maritime Commission published a final rule on demurrage and detention billing, effective May 28, 2024. Part of it, at 46 CFR 541.4, restricted who a carrier could invoice: the party that contracted for the transportation, or the consignee, and not several parties at once.

On September 23, 2025 the US Court of Appeals for the DC Circuit set that provision aside. The FMC then formally removed it from the Code of Federal Regulations, effective December 29, 2025.

So as of today, that particular protection is not current law. The rest of the billing rule, including what an invoice has to contain and the windows for disputing it, was not what the court set aside. If you are relying on an article written in 2024 about who may bill you, you are relying on something a court has since vacated.

What to do about it

Know which free time you are actually counting. The number in the port's tariff is the port's. Your carrier gave you its own, in your contract or on the bill of lading, and that is the one your invoice will be measured against.

Get the container moving before the carrier's clock expires, not the port's. Customs release and terminal free time are separate: a container can be fully released by CBP and still be piling up charges because nobody booked a truck.

And when a bill arrives that you think is wrong, check who sent it before you argue. A carrier charge and a port charge go to different desks, and sending a good dispute to the wrong one just spends your time.