Guide
Container tracking for fresh produce importers
Why tracking positions are often wrong, what the milestones actually mean, and how to turn a container number into a decision you can act on.
6 min readBy Edouard Brière · Published
A reefer of Chilean cherries left Valparaíso six weeks ago, bound for Rotterdam, and it is sold. Every importer watching that box is really asking one of three questions: will it arrive when I sold it for, is the fruit still going to be worth what I paid, and do I need to do something today. A tracking page that answers “in transit” answers none of them.
This guide covers what container tracking data is, where it comes from, why the position on the map is frequently wrong, and which events are worth building a process around.
What “tracking” is made of
A container’s journey is reported through three different systems that do not agree with each other.
Carrier milestones come from the shipping line. Gate-in, loaded on vessel, vessel departed, transshipped, discharged, gate-out, empty returned. They are authoritative (the line is the party that did the thing), but they are published in batches, sometimes hours after the event, and occasionally out of order.
AIS vessel positions come from the ship, not the container. Vessels broadcast their position over AIS, terrestrial receivers and satellites pick it up, and that is what draws the line on the map. It tells you where the vessel is, which is only where your container is if your container is still on that vessel.
Terminal and port data covers what happens between discharge and gate-out: the part of the journey where demurrage accrues, and the part with the worst data coverage.
Most tracking products blend all three and present the result as one confident-looking dot. Knowing which source a fact came from tells you how much to trust it, and AIS vs carrier EDI is the pair that disagrees most often. Holding all three in one place is what a container visibility platform is for.
Why the position on the map is often wrong
The dot is interpolated more often than importers realise.
A vessel mid-ocean may go hours between AIS fixes, especially outside satellite coverage. Rather than show a stale position or nothing at all, most systems draw a straight line between the last known fix and the expected next waypoint and place the vessel somewhere along it, moving at its average speed. That dot is a guess that happens to look believable.
It is usually a good guess. It stops being one when the vessel does something the interpolation cannot know about: slow steaming to save fuel, waiting at anchor for a berth, diverting around weather, or being rerouted. Then the interpolated dot keeps gliding toward the destination on schedule while the vessel itself sits still.
The practical consequence: a dot that is moving smoothly is not evidence that the vessel is moving. Treat the timestamp of the last real fix as the fact and the position as an estimate. When the two are far apart, the ETA built on top of it is worth less than it looks.
The events actually worth watching
Out of a dozen or more milestones, four change what you do:
Departure from origin. Confirms the container is on the water and on which vessel. Until this event arrives, what you have is still a booking and not yet a shipment.
Transshipment. The container moves to a second vessel at a hub port such as Algeciras, Singapore or Colón. This is the most common point at which a container stops matching its ETA without anyone being told. If it misses the connection it waits for the next one, which can be a week. It is also the point at which tracking a vessel stops telling you about your container.
Discharge at destination. Starts your free time, which the ETA does not. Everything about avoiding demurrage depends on knowing this date as it happens rather than reconstructing it from an invoice later.
Gate-out. The container has left the terminal. Demurrage stops, detention starts.
What an ETA is worth
An ETA is a forecast, and its quality decays with distance. Six weeks out it is a schedule; six days out it is an estimate; six hours out it is a fact. Importers who treat all three as the same number are the ones who book hauliers twice.
Why does my ETA keep changing? covers this in full. Two habits help. Watch the ETA’s movement rather than its value — a date that has slipped three times in a week will slip again, and that pattern is visible long before the final delay is. And separate the vessel’s ETA from your container’s: after a transshipment they are different numbers, and only one of them is about your fruit.
Tracking a reefer specifically
A reefer container carries a fourth data stream that dry cargo does not: the temperature log from the refrigeration unit itself, recorded through the voyage and downloadable at the end.
This is the record that settles quality claims. A load that arrives soft is either a pre-shipment problem or a cold-chain problem, and the temperature log is the only thing that distinguishes them. It is worth pulling as a matter of routine rather than only when there is an argument, because by the time there is an argument the container has usually been returned.
Reefers also run on shorter free time at higher rates. The same delay that is an annoyance for dry cargo is a real cost here, which is why the discharge event matters more for a reefer than for anything else on the vessel.
Position, condition and remaining shelf life are three separate questions, and answering all three is what cold chain visibility means. Newer boxes answer the second themselves through reefer monitoring; the rest still hold their log until arrival.
Turning this into a process
Tracking is only worth doing if something happens as a result. A process that works:
- Confirm the booking became a shipment. No departure event, no shipment.
- Set the alert on transshipment, not on arrival. By arrival it is too late to do anything but pay.
- Watch for silence. A container that has stopped producing events is the strongest signal in the data, and no tracking page shows it — an absent event does not render.
- Act on discharge, not on ETA. Book the haulier and finalise clearance when the discharge event arrives, whatever the forecast said.
- Close the loop on the empty. Detention runs until the empty is returned, which is the step everyone considers somebody else’s job.
Trackberry turns these events into the three answers this guide opened with, for the containers you already have on the water. See how it works for produce importers, or book a 20-minute chat.
FAQ
Why does my container’s position not match the shipping line’s website?
Because the two are answering different questions from different sources. The line reports milestones it has recorded; a tracking map shows a vessel position derived from AIS, often interpolated between fixes. Neither is wrong. The line’s milestone is a record of something that happened, and the map position may be an estimate of something happening now.
How accurate is a container ETA?
Accurate enough to plan against within a few days of arrival, and not accurate enough to commit to six weeks out. The most useful signal is how stable the date is. An ETA that keeps moving tells you something the date alone does not.
Can I track a container without the shipping line’s reference?
Usually yes — a container number or a bill of lading number is enough to look up a shipment with most lines. What you get back varies: some lines publish a full milestone history, others only the current status.
What happens to tracking after a transshipment?
The container changes vessel, so anything following the original vessel stops being about your cargo. This is the point where tracking quality most often degrades, and where a container most often loses a week without the ETA moving to match.
Does tracking tell me if the fruit is still good?
No — but a reefer’s temperature log comes close. Tracking tells you where the container has been and how long it took; the temperature log tells you what the cargo experienced while it did. For a quality claim you need both.
See it in practice
Two minutes on what this looks like when the tracking, the paperwork and the ETA sit in one place.
In this guide
- Why tracking positions are often wrong The dot on a container tracking map is usually a guess. Here is how interpolation works, when it fails, and how to tell a real AIS fix from an estimate.
- IMO number vs MMSI number: how to identify a vessel What an IMO number and an MMSI number are, who assigns them, where to find them, and which one to trust when you check the ship carrying your fruit.
- Why does my ETA keep changing? Because it was never a promise. What an ETA is actually built from, why it moves, and which movements are worth acting on rather than watching.
- How to track a reefer container end-to-end What to watch at each stage of a refrigerated container's journey, which events actually change what you do, and why the temperature log matters most.
- Booking through a forwarder or direct with the carrier What each way of booking costs a produce importer, what changes when the box is a reefer, and why the reference you hold decides what you can see.
- The shipping data standards that actually exist, and what they leave out Shipping has three generations of data standards, each covering one slice of the chain. Which slice is which decides where your data stays a PDF.
- What is a reefer container? Sizes, setpoints and what fails Reefer means refrigerated. What a reefer container is, 20ft and 40ft reefer sizes and specs, setpoints, controlled atmosphere and the usual failures.
- What a modern reefer can and cannot do for your fruit A reefer removes heat rather than adding cold. What that means for your setpoint, whether controlled atmosphere earns its cost, and what is changing.
- Understanding the documents in a fresh produce import What each document in a produce import is for, who issues it, when it has to arrive, and which ones stop your container leaving the terminal.
- Packing lists in fresh produce shipping: a complete guide What is on a produce packing list, why no two exporters build one the same way, and an annotated example of the fields you need pulled out.
- Why document automation in produce trade was impossible until now Legacy OCR could never read a produce packing list — sixty growers, sixty layouts, four languages, phone-camera scans. What changed, and what still fails.
- Manual data entry from shipping documents: what it really costs Someone in your office will key eleven working days of packing lists this season. What that costs, where the number comes from, and how to find yours.
- Bill of lading explained for produce importers Which fields on a B/L your tracking needs, which ones customs reads, and how to choose between an original, a telex release and a sea waybill.
- Reefer cargo claims: how importers document and win them Temperature-damaged fruit and a carrier saying no. What to do in the first 72 hours, which evidence decides it, and the deadlines that end a claim early.
- Phytosanitary certificate: what produce importers must check What a phytosanitary certificate certifies, who issues it, how ePhyto changes the paperwork, and the errors that hold fruit at the EU or UK border.
- Demurrage and detention: how importers lose money on free time Where the charges come from, why they escalate, the mistakes that cause most of them, and what actually works to avoid paying them.
- Disputing a demurrage invoice: why paying first loses the argument Pay under protest and your leverage is gone. How to challenge demurrage and detention charges when the cargo is perishable and cannot wait.
- Reefer shortages: why there is never a box when you need one Reefer equipment is scarce by design, scarcest exactly when your season peaks. What causes it, what it costs, and the parts you can influence.
- Your container got rolled: what actually happened and what to do now The vessel sailed and your reefer did not. How to confirm it was a rollover, what to decide in the first two days, and what the line will give you.
- Transit time is shelf life: the real cost of rerouting A longer voyage does not add cost at the margin. It moves days out of the part of the journey that sells fruit and into the part that does not.
- El Niño and fresh produce shipping: what it changes for importers El Niño moves your harvest windows and your transits in the same weeks. Which origins it hits, which it spares, and what it does at the Panama Canal.
- Fresh produce chokepoints: a geopolitical guide for importers Who can close Panama, Suez, Gibraltar, Hormuz and Malacca, why they would, and what each closure costs a reefer of fruit in days of shelf life.
- Why 19th-century sailing routes might matter again for fresh produce Wind-assisted ships are routed for wind, not distance. What that changes on a reefer lane, and why it costs you no days.
- Food miles are misleading: what actually drives your import carbon footprint Distance is a poor guide to carbon. Why the mode matters more than the miles on a produce lane, and what a retailer can actually require you to report.