ANKPOST
中文

Wiki

What is Detention in Shipping? Fee Structure & Container Return Guidelines

By ANKPOST Intelligence · 2026-06-12

What is detention in shipping?

Detention (also called per diem) is a fee charged by ocean carriers when an importer retains a container outside the port terminal past the carrier's allotted free time, tracking from gate-out until the empty unit is returned to the carrier's designated depot — distinct from demurrage, which applies to time inside the terminal. Independent dispatch data indicates that standard free time outside the gate at West Coast ports is typically 3-5 business days, and on-ground drayage logs show containers retained past this window are returned a median of 1-2 days late during normal conditions, extending to 4-6+ days late during periods of depot congestion or chassis shortages.

In this article

Cost structure / standard tiers

Per diem rates accumulate daily once the outside-gate free time is exceeded, on a sliding scale similar to demurrage.

Days Past Free Time Typical Daily Rate
Days 1-4 $150-$225/container/day
Day 5 onward $350+/container/day
Carrier-owned container (COC) Subject to standard per diem structure above
Shipper-owned/leased container (SOC) Not subject to carrier per diem; lessor may apply separate terms

Standard free time outside the gate is typically 3-5 business days, after which the daily rate steps up sharply at the day-5 threshold.

Risk mitigation / operational guidance

Canonical URL: https://ankpost.com/wiki/detention-fees-explained