Demurrage and detention are two of the most misunderstood — and most expensive — costs in container shipping. This guide breaks down what they are, how they work at South Florida ports, and what you can do to minimize them.
Demurrage vs. Detention: Know the Difference
These two terms are often used interchangeably, but they're distinct charges with different triggers:
Demurrage is the fee charged by the ocean carrier when an import container remains at the marine terminal beyond the allotted free time after vessel discharge. The container hasn't left the port yet — it's sitting in the terminal yard, and the shipping line wants it moved.
Detention is the fee charged after the container has left the terminal. It's the cost of keeping the ocean carrier's equipment (the container itself, and sometimes the chassis) beyond the allowed time for unloading and returning the empty.
Both charges are set by the ocean carrier's tariff schedule, not by the port terminal. The port provides the physical space; the carrier owns the box and sets the rules.
Free Time at South Florida Ports
Free time is the grace period between when a container is discharged from the vessel and when demurrage charges begin. At PortMiami and Port Everglades, most major ocean carriers provide:
Standard dry containers: 3–5 calendar days of free time.
Specialty containers: 2–3 calendar days (shorter because overweight containers require power and terminal resources).
Overweight or special equipment: Varies by carrier; often the same as standard.
Free time starts when the vessel completes discharge — not when you receive notification, not when customs clears the container, and not when your drayage carrier is available. The clock is running from day one.
The Real Cost: A Practical Example
Consider a shipper importing 15 containers per week through PortMiami. The ocean carrier provides 4 free days. Your drayage provider picks up 12 containers within free time, but 3 containers sit an extra 3 days each due to a customs hold and a scheduling conflict.
At $200 per day demurrage: 3 containers × 3 days × $200 = $1,800 in one week.
Over a year, that's $93,600 — for a problem that's entirely preventable with better coordination between your customs broker, drayage carrier, and warehouse.
Why Containers Get Stuck
Customs Holds
CBP can hold any container for inspection, agricultural examination, or regulatory review. While some ocean carriers offer free time extensions for government holds, this isn't automatic — you typically need to submit a written request with documentation proving the hold was outside your control.
Late Documentation
If your customs broker files late, the container can't be released. Even a one-day delay in entry filing can push a container past its free time window. Pre-filing entries before vessel arrival is the single most effective way to prevent documentation-related demurrage.
Drayage Capacity Shortages
During peak seasons or when vessel bunching floods terminals with containers, drayage capacity tightens. If your carrier can't get a truck to the terminal within free time, you pay demurrage. Asset-based carriers with their own fleet are less susceptible to this — they don't compete for spot market capacity.
Terminal Appointment Backlogs
PortMiami terminals use appointment systems. If slots fill up during your free time window, you may not be able to schedule a pickup even if everything else is ready. Booking appointments as soon as customs releases your container is critical.
Warehouse Receiving Delays
Sometimes the container gets picked up on time, but the receiving warehouse can't accept it — full dock, no appointment available, or closed for the day. The container sits on a chassis, and detention starts accruing. Coordinating warehouse receiving with drayage dispatch prevents this.
Seven Strategies to Minimize Demurrage and Detention
1. Pre-Clear Customs
File entry documentation 3–5 days before vessel arrival. When the container hits the terminal, it's already cleared and ready for pickup on day one of free time.
2. Use an Asset-Based Drayage Carrier
A carrier that owns its trucks doesn't need to find capacity on the spot market. They can dispatch immediately when your container is released, even during peak periods.
3. Book Terminal Appointments Immediately
The moment your container shows as released, book the pickup appointment. Waiting even one day during busy periods can cost you a free day.
4. Coordinate Drayage and Warehousing
When the same company handles both drayage and warehouse receiving, there are no scheduling gaps. The driver picks up the container, delivers to the warehouse, and the empty return is scheduled as part of the same operation.
5. Track Vessel Schedules Proactively
Know when your vessel is arriving — and when it actually discharges. Early arrivals can catch you off guard if you're not monitoring. Use carrier tracking tools or platforms like MarineTraffic.
6. Negotiate Extended Free Time
If you ship consistent volume with an ocean carrier, negotiate for additional free days. Even one extra day can make a meaningful difference across hundreds of containers per year.
7. Document Everything for Disputes
Under FMC rules, demurrage must be reasonable and serve as an incentive to move cargo. If charges result from circumstances outside your control, you can dispute them. Keep records of customs release timestamps, appointment confirmations, terminal closures, and any carrier-caused delays.