How to track a reefer container end-to-end

A reefer container produces more data than any other box on the vessel, and most importers use almost none of it. This walks the journey stage by stage: what is knowable at each point, what is worth acting on, and what to collect before it becomes hard to get.

Before departure #

Confirm the setpoint and ventilation before the container is loaded. This is the only stage where they can still be changed, and getting them wrong is not recoverable at destination. Temperature, fresh air exchange rate, and controlled atmosphere if you are paying for it — all commercial decisions made before the doors close.

Get the container number. You do not need the transport document to start tracking; the container or bill of lading number is enough. Registering it early means the tracking history starts from the beginning rather than from whenever the paperwork caught up.

Departure #

The event to wait for is loaded on vessel, followed by vessel departed. Until the first of these lands, you have a booking rather than a shipment — and the gap between them is where a rollover shows up as an absence rather than a notification.

A vessel that sails without a load event for your container is the earliest reliable signal that something has gone wrong. Nobody will call you about it.

At sea #

This is the stage where importers watch most closely and there is least to see, which is a poor combination.

Carriers publish milestones at port calls. Mid-ocean, days or weeks can pass with nothing new, and that is normal — not a failure. What is genuinely moving is the vessel’s AIS position, which rides a separate feed.

So the useful question at sea is not “has anything happened” but “is the silence normal”. Two clocks answer it:

• Carrier published — when the line last reported a milestone. Quiet for weeks mid-voyage is expected.
• Vessel position moved — when the ship was last confirmed at a real AIS fix. If this is recent, the voyage is fine.

A quiet carrier plus a moving vessel is a healthy shipment. A quiet carrier plus a stationary vessel is worth a question. Any alerting worth having makes that distinction rather than firing on carrier silence alone — silence mid-ocean is the normal case, and an alert that cries wolf every voyage gets muted by the second season.

Transshipment #

If your routing has one, this is the highest-risk point in the journey — see why tracking positions are often wrong for why the map stops helping here.

What you want is a discharge at the hub followed within hours by a load onto the onward vessel. A discharge with no matching load, days later, means the connection was missed and the box is waiting for the next sailing. On a weekly service that is seven days of shelf life.

Arrival and discharge #

Discharge from the vessel is the event that matters most in the whole journey, and it is the one most importers watch least. It starts your free time, and for a reefer that clock is short — often 2–4 days against 5–7 for dry.

Not the ETA. Discharge. A vessel arriving two days early shortens your window by two days, and an ETA-based plan will not notice.

Act on this event, not the forecast: confirm the haulier, confirm the customs entry is filed, confirm the cold store has a bay.

Gate-out and the road leg #

Gate-out ends demurrage and starts detention. The container is now yours to hold, and the meter is running at reefer rates.

The reefer needs power on the road — a genset, or a short enough run that thermal mass covers it. A container waiting for an unloading bay with no power is a cold-chain risk, not just a scheduling one.

Strip and empty return #

Detention runs until the empty is returned to the depot, not until you unload it. A stripped container sitting in your yard is still on hire. This is the step everyone treats as somebody else’s job, and it is where the last avoidable charges accumulate.

Book the empty return slot early — depots run out of them.

Before you return it: pull the temperature log #

Every reefer records its actual temperature through the voyage. Download that log as a matter of routine, on arrival, every time.

It is the only document that distinguishes a pre-shipment quality problem from a cold-chain failure. If fruit arrives soft, the log is what tells you whether it was packed warm, whether the unit held setpoint, and whether there was a gap. Without it, a quality claim is one party’s word against another’s.

Getting it after the container has gone back is possible, slow, and sometimes not possible at all. The cost of pulling a log you never need is nothing.

The short version #

FAQ #

What is the single most important event to watch? #

Discharge from the vessel. It starts your free time, and almost every avoidable demurrage charge traces back to someone learning about it after the fact rather than as it happened.

Why does my carrier report nothing for weeks mid-voyage? #

Because carriers publish milestones at port calls, and mid-ocean there are none. Check the vessel’s AIS position instead: recent movement means the voyage is fine and the carrier is simply quiet.

When should I download the temperature log? #

On arrival, every time, whether or not there is a problem. Once the container is returned the data gets harder and slower to obtain, and by the time a quality dispute exists it is usually too late to go looking.

Does detention stop when I unload the container? #

No — when the empty is returned to the depot. A stripped container in your yard is still on hire, at reefer rates.

How much free time does a reefer get? #

Typically 2–4 days at destination against 5–7 for dry, at a higher daily rate once it runs out. It varies by line and contract, so check yours rather than assuming a standard number.