Demurrage and Detention Charges: What Delays at Port Actually Cost

• Demurrage — charged by the shipping line for the container sitting inside the port or terminal beyond the agreed free time, before it's picked up for delivery.
• Detention — charged for the container being held outside the port (at your warehouse or premises, or in transit) beyond the agreed free time, before the empty container is returned to the shipping line.

Both are separate from freight itself and from port handling charges — they're specifically penalties for holding the shipping line's equipment (the container) longer than the agreed window.

Free time is the number of days you're allowed to use the container — at the terminal (demurrage) or outside it (detention) — before charges start accruing, and it typically runs from the vessel's discharge date, not from when you're notified or when customs clearance completes. Free time is commonly in the range of 3–7 days per leg depending on the shipping line, port, and any specific arrangement negotiated, and it is negotiable, particularly for regular-volume shippers.

This depends on who controls the shipment at destination, not on which side of the transaction arranged the freight. Under most common Incoterms (FOB, CFR, CIF), customs clearance and onward handling at destination sit with the buyer, which means the buyer is also typically the party exposed to demurrage and detention if clearance or container return is delayed on their end. Confirm this explicitly rather than assuming it's covered by whatever freight arrangement is already in place.

The free-time clock starts on discharge, but a first-time importer's own customs clearance, inspection, or payment-release process can easily consume several days without anyone treating it as urgent — by the time clearance is sorted, free time has often expired. Having your customs broker and transport arranged before the vessel arrives, rather than starting that process after arrival, is the single most effective way to avoid these charges.

• Confirm the exact free-time allowance (in days, for both demurrage and detention) before the shipment leaves origin, not after it arrives.
• Line up your customs broker and inland transport in advance of the vessel's estimated arrival, not after it docks.
• Track the discharge date directly, since that's when the free-time clock starts — not the vessel's arrival date or your own notification date.
• Return empty containers promptly once unloaded, since detention continues accruing until the empty container is back with the shipping line.