The cargo is cleared. The duty is paid. The truck has delivered and the goods are on your shelves. Then, a week later, an invoice arrives like a guest who missed the wedding but still expects to be fed. It says demurrage. Or detention. Sometimes both.

These charges surprise importers more than any other bill in shipping, and on a container that sits too long they grow fast. The good news is that they are predictable, and mostly avoidable, once you know who is charging what.

Three different clocks

When a full container lands at Mombasa, three separate meters can start running. Different parties bill them, which is why people mix them up.

• Demurrage is charged by the shipping line when its full container stays in the port or CFS beyond the line’s free days.
• Detention is charged by the shipping line when you keep its container outside the port, at your warehouse or on a truck, beyond the free days allowed before you return it empty.
• Storage is charged by the Kenya Ports Authority, or by the Container Freight Station holding your box, when cargo stays beyond the free storage period.

Put simply: demurrage and detention are rent on the box, which belongs to the line. Storage is rent on the ground the cargo sits on. You can pay all three on the same container, which is the shipping equivalent of paying for the house, the furniture and the parking.

A worked example

A container is discharged at Mombasa on 2 March. Say, for example, the shipping line allows seven free days, so its free time ends on 8 March. The importer’s documents are not ready, and the container is collected on 12 March.

• The line charges demurrage for 9, 10, 11 and 12 March: four days at the line’s daily rate.
• If the port or CFS free period ended before 12 March, there is also a storage charge for those days.
• The importer then keeps the container at the warehouse for ten days before returning it empty. If the line allows five days outside the port, it charges detention for the extra five.

The free days in this example are for illustration. They vary by shipping line, by container type and by what you negotiated at booking.

Why the charges climb so quickly

Lines usually charge in tiers: a lower daily rate for the first days after free time ends, then higher rates the longer the box stays. KPA storage works the same way. It is a staircase, not a ramp, and every step is steeper than the last. KPA’s Tariff Book 2025, in force since 22 December 2025, raised many port charges, including storage, so a week of delay now costs more than it did a year ago.

How to avoid paying

1. Prepare documents before the ship arrives. The IDF, the CoC where needed, the bill of lading and the invoice should all be ready and consistent. Most demurrage we see starts with a missing or mismatched document.
2. Negotiate free days at booking. Lines will often extend free time for regular customers or larger volumes, but only if you ask before the cargo sails. After it sails, you are asking a favour.
3. Pay duties promptly. Customs release cannot happen until taxes are paid.
4. Plan the unloading. Have labour and space ready at your premises so the container can be emptied and returned the same day or the next.
5. Return empties to the right depot. Check which empty depot the line has named. Delivering to the wrong one means extra days and extra trucking.
6. Check every invoice. Compare the dates billed with the discharge date, gate out and empty return records. Mistakes happen, and billed days can be challenged.

Consider LCL for small shipments

If you only have a few cubic metres of goods, shipping LCL (a shared container) means you are not exposed to container demurrage and detention in the same way, although CFS storage still applies if you collect late. Our article on paying per KG or per CBM from China explains when LCL makes sense.

Let us watch the clock for you

We track free days from the moment the vessel berths and warn you before the meters start. Think of us as the friend who taps your shoulder before the parking attendant arrives. See our clearing and forwarding service or ask for a quote.

Call +254 722 375 423 or +254 741 444 444, WhatsApp @sidoman254 or @Sidoman_, or email info@sidoman.com. Sidoman Plaza, Ground Floor, Lumumba Road (Sidoman Street), King’orani, Mombasa.

The ship keeps its schedule. Keep yours, and that uninvited invoice never gets an invitation.