What is detention in container shipping?

In container shipping, detention refers to a fee charged by the shipping line to the cargo owner or the charterer for retaining the container beyond the agreed upon free time at the port or at the destination. Similar to Demurrage, detention is the fee charged for not returning the container in the agreed time after it has been loaded or unloaded.

It is intended to compensate the shipping line for any loss of revenue or additional expenses incurred as a result of the delay in returning the container. The free time and detention fees are generally specified in the bill of lading or other shipping contract between the cargo owner or charterer and the shipping line.