What do ETS, ATS, ETA and ATA mean?
Two letters carry the whole meaning.
- The first letter is E for estimated or A for actual. An actual is a confirmed event that has happened; an estimate is a prediction that can still move.
- The last letter is the event: S for sailing, D for departure, A for arrival.
| Label | Meaning |
|---|---|
| ETS, shown as ETD on some accounts | Estimated time of sailing from the port of loading |
| ATS | Actual time of sailing from the port of loading, once the event is confirmed |
| ETA | Estimated time of arrival |
| ATA | Actual time of arrival, once the event is confirmed |
These are one column, not two. It is labelled ETS / ETD, and which name you see is set once per account. There is no equivalent rename for ATS.
ETD and ATD also appear per transhipment port, as T/S Port 1 ETD, T/S Port 1 ATD and so on.
Those are departures from a transhipment port, which is a different event from the sailing at the
port of loading. If you are comparing an ATD against an ATS, check which port each belongs to first.
ATS means sailed
S is for sailing. ATS is set from the vessel actually departing, or from the container being loaded on the vessel. A gate-in at the port of loading is not a sailing, and is not supposed to produce an ATS.
This matters because a container can be delivered to the terminal days before the vessel leaves. If you see an ATS that matches the day the box was delivered rather than the day the vessel sailed, that is worth reporting with the reference.
Arrival is not discharge
At the port of discharge there are two separate events, typically a day apart:
- Vessel arrival - the ship arrives
- Discharge - your container comes off the ship
Some carriers publish both. Others publish only one, in which case Dockflow derives the other from vessel tracking and terminal data. A date that looks a day out against a carrier portal is very often these two events being compared to each other. See why Dockflow shows something different from the carrier.
The milestone codes
Every tracking event carries a code. These are what you see in exports and over the API.
| Code | Event |
|---|---|
| GE | Empty equipment dispatched |
| GN | Gate in |
| AE | Loaded on vessel |
| VD | Vessel departure |
| VA | Vessel arrival |
| UV | Unloaded from vessel |
| GT | Gate out |
| GD | Gate out to an inland depot |
| GR | Empty equipment returned |
A code can carry a leg suffix, for example VD-F, indicating which leg of the journey the event
belongs to rather than a different kind of event.
Which date answers which question
| Your question | The date to read |
|---|---|
| When does the vessel leave? | ETS, or ATS once it has sailed |
| When does the vessel get in? | ETA at the port of discharge, or ATA once it has arrived |
| When can I collect the container? | Discharge, then gate out - not vessel arrival |
| Is it still at the terminal? | Gate out. Until then it has not left |
| Is the box back? | Empty equipment returned |
If the date you are reading is at a transhipment port rather than the final port of discharge, that is a different question again - Dockflow labels transhipment separately. See no tracking data for why a final leg can be missing.
Related topics
- ETA first ever, ETA confirmed, ETA latest - which ETA metric to use for planning versus performance
- Data differs from carrier - when two sources show different dates
- Data is wrong - when a date is genuinely incorrect
- Where Dockflow gets its data - carrier, terminal and vessel tracking
Need help?
- Email support - [email protected]
- In-app chat - click the chat icon in the bottom right
Last updated: August 17, 2026