The delay that happens after the voyage
Most people picture shipping delays as something that happens at sea. But some of the most stubborn delays happen within sight of the destination, while a ship idles outside a port waiting for a berth. A terminal has a fixed number of berths, cranes, and yard slots. When more ships arrive than the port can work, they queue. That queue is port congestion, and the wait can add days to a voyage that was otherwise on time.
The scale of it over the last two years has been hard to ignore. According to a review of global port performance, 60 of 88 major ports, about 68%, recorded longer average vessel waiting times in 2024 than in 2023. This was not one bad port on one bad week. It was a broad, worldwide slowdown, and it flowed straight into every arrival date that depended on those ports.
68% of major ports got slower
In 2024, more than two-thirds of the world's busiest container ports saw ships wait longer for a berth than they did in 2023, based on a review of 88 ports. Congestion is not a local problem you can sidestep by avoiding one terminal. When it spreads, it reshapes arrival times across whole trade lanes at once.
What actually causes a port to back up
Congestion is rarely one thing. It builds when several pressures stack up at the same terminal at the same time:
- Bunched arrivals. When ships that were nicely spread out get delayed and then arrive together, a port designed for a steady flow suddenly faces a crowd. The Red Sea reroutes did exactly this, scrambling schedules so vessels reached Europe and Asia in clusters.
- Not enough berth, crane, or yard capacity. A terminal can only work so many ships at once. If the yard is already full of containers waiting to be collected, there is nowhere to put the next ship's boxes.
- Labour and equipment shortages. Too few dockworkers, truckers, or working cranes slows how fast a ship is unloaded, and a slow berth is a berth the next ship cannot use.
- Landside gridlock. If trucks and trains cannot clear containers out of the port fast enough, the yard clogs and the congestion backs up from the land, not the sea.
- Weather and disruption. Storms, strikes, and outages stop work entirely, and the backlog that forms while a port is shut can take weeks to clear once it reopens.
The 2024 to 2025 congestion wave
The recent congestion had a clear trigger. When attacks in the Red Sea pushed carriers to sail around the Cape of Good Hope, the reroute added thousands of miles and bunched vessel arrivals at the major hubs. This is not a new phenomenon: at the peak of the pandemic-era crunch in early 2022, more than 100 container ships waited off the ports of Los Angeles and Long Beach at once. But the 2024 to 2025 wave was more global, and the pressure showed up fast:
- Singapore, the world's second-busiest container port, saw waits stretch from the usual half-day to three or four days, peaking near nine days in late 2024, with hundreds of thousands of TEUs queuing offshore.
- Durban saw container dwell times climb to around 11.3 days as rerouted traffic piled up.
- North European hubs like Rotterdam and Antwerp saw waiting times swell by 20 to 30%, and some terminals temporarily stopped accepting certain cargo to relieve the pressure.
By April 2025, more than 935,000 TEUs of capacity was waiting at anchor outside European ports, close to a third of all global port congestion at that moment. It eased over the following months, with the share of container capacity stuck outside ports improving from around 10% in May to 8.4% by mid-2025, but even the better figure still means a large amount of cargo sitting still.
935,000 TEUs waiting off Europe
At its April 2025 peak, nearly a million TEUs of capacity sat at anchor outside European ports, roughly a third of global congestion concentrated in one region. By late May, ships were still averaging five to six days waiting for a berth at key European hubs. That is a week of delay added at the very end of the journey, after the ocean crossing is already done.
Why a congested port costs more than a few days
A ship stuck outside a port is not a contained problem. The wait ripples outward into costs that land in several places:
- Free time evaporates. Demurrage and detention clocks are tied to events like discharge and gate-out. Congestion can eat your free time before you can even collect the box, turning a delay into a fee.
- Missed connections and blank sailings. A ship delayed by congestion at one port can miss its slot at the next, and carriers sometimes cancel sailings to reset bunched schedules, pulling capacity right when you need it.
- Inventory whiplash. Cargo that all arrives late, then all arrives at once when the backlog clears, swings a warehouse from empty to overflowing, which is expensive at both ends.
- Costs that spread inland. A congested port pushes up trucking and storage demand around it, so the delay raises costs well beyond the terminal gate.
You can't uncongest a port, but you can see it coming
No shipper can add a berth to Singapore or clear a backlog at Rotterdam. What you can do is stop being surprised by congestion, because unlike a lot of supply chain risk, it is visible in advance. Ports do not clog instantly. The queue builds over days, and the signals, longer waits, rising dwell times, and growing vessel counts at anchor, are all observable before your own ship arrives.
That visibility changes what you can do about it. If you can see that a transshipment hub is backing up, you can weigh an alternative routing at booking. If your ship is heading into a congested port, a predictive ETA that already factors in the wait tells you the realistic arrival, not the optimistic one. And watching congestion alongside your live shipments means the delay reaches you as information you can act on, rather than as a box that simply shows up late.
One of the few risks you can see building
A war or a storm arrives suddenly. A port backs up gradually, over days, in plain view. That makes congestion one of the few major delay risks you can genuinely plan around, as long as you are watching the right signals before you commit a shipment to a route.
How to stay ahead of port congestion
A few habits keep congestion from turning into a surprise:
- Check congestion before you route. Look at the current state of your origin, destination, and any transshipment hubs before booking, and favour a less congested path when you have the choice.
- Work from a congestion-aware ETA. Treat the booked arrival as optimistic when a port is backed up, and plan around a live ETA that reflects the real wait.
- Watch your transshipment points, not just the endpoints. A lot of congestion delay happens at the hub in the middle, where your cargo changes ships, so keep an eye on those ports too.
- Protect your free time. Know when your demurrage and detention clocks start, and line up trucking and collection early so a congested port doesn't turn into storage fees.
- Keep every shipment in one view. When congestion hits a port, you want to see instantly which of your shipments run through it, rather than checking them one at a time.
The bottom line
Port congestion is the delay that hides at the finish line. A shipment can sail on time and still lose a week waiting for a berth, and across 2024 and 2025 that happened at most of the world's major ports at once. You cannot clear a backlog, but you do not have to be blindsided by one. Congestion builds slowly and in the open, which makes it one of the few risks you can actually get ahead of. The shippers who do it well check the ports before they route, plan around a realistic arrival, and watch congestion next to their own cargo, so a backed-up terminal becomes a decision they make rather than a delay they discover.