How ONE Container Tracking Actually Works: What the Portal Shows, What It Doesn't, and What the Events Mean

Key Takeaways

ONE’s tracking portal at ecomm.one-line.com accepts container numbers, booking numbers, and B/L numbers — but only Master B/Ls. House B/Ls are not supported.
“Vessel Arrival” on ONE means at anchor or in the vicinity of the port — not berthed. This can precede actual berthing by 3 to 48 hours and is the single biggest gotcha for teams tracking ONE alongside other carriers.
ONE launched an enhanced cargo tracking interface in April 2025 with a vertical timeline, progress bar, color-coded deadline alerts, and exception alerts.
Legacy container prefixes from NYK, MOL, and K Line are still in circulation. ONEU is the primary prefix, but NYKU, MOLU, KKLU, and KKFU (more common than KKLU) are all trackable.
The Premier Alliance with HMM and Yang Ming launched February 9, 2025, with ~340 vessels. Alliance schedule reliability sits at approximately 56.9% — the lowest among the three major alliances.
Data lag runs 6-12 hours with backend updates 2-3 times daily.
ONE is a DCSA founding member with T&T 2.2 support and a February 2025 GSBN partnership for DCSA electronic bills of lading.

Schedule reliability figures, update cadence estimates, and carrier performance data referenced in this guide are based on third-party industry reports and may reflect specific monthly snapshots rather than sustained averages. Carrier systems and capabilities are subject to change.

Who This Is For

This guide is for freight forwarders, importers, and operations teams tracking shipments on ONE — including those transitioning from legacy NYK, MOL, or K Line tracking systems. If you track across multiple carriers and need to understand why ONE’s “Vessel Arrival” does not mean what it means on Maersk or CMA CGM, start here. For the full cross-carrier comparison, see our event naming guide.

What the Portal Shows You

ONE was formed in 2017 from the container shipping divisions of NYK, MOL, and K Line, and launched operations in April 2018. The company is headquartered in Singapore with executive offices in Tokyo. The tracking portal at ecomm.one-line.com is the primary interface for all cargo visibility.

In April 2025, ONE rolled out a significantly enhanced tracking interface. The “Newly Enhanced Cargo Tracking” replaced the older flat timeline with a vertical progress display, a visual progress bar, color-coded deadline alerts (for demurrage and detention free time), and exception alerts that flag when something deviates from the planned schedule. These changes make ONE’s portal more informative than it was even a year ago.

The portal accepts container numbers, booking numbers, and B/L numbers. One critical limitation: ONE accepts only Master B/Ls. If you are a forwarder tracking under a House B/L, you will need the Master B/L number to get results. This catches teams by surprise — especially those migrating from carriers that accept House B/Ls.

Legacy container prefixes are still active. ONE’s primary prefix is ONEU, but you will encounter NYKU (NYK), MOLU (MOL), KKLU, and KKFU (K Line — KKFU is more common than KKLU in practice). All are trackable on ONE’s portal. If you are tracking a container with one of these legacy prefixes and it does not resolve on ONE’s portal, double-check the container number — some very old units may have been rebranded or retired.

Event Names and What They Mean

ONE’s event labels are relatively clean, but one label — “Vessel Arrival” — means something different than what most teams expect. The table below maps each ONE label to what actually happened and the DCSA code.

ONE Event Label	What Actually Happened	DCSA Code
Booking Confirmed	ONE accepted the booking and allocated space	—
Container Gated In	Laden container entered the origin terminal	GTIN
Loaded on Vessel	Container was lifted onto the vessel at port of loading	LOAD
Vessel Departure	Ship left the port of loading	DEPA
In Transit	Container is on the water between ports	—
Vessel Arrival	Vessel is at anchor or in the vicinity of the port (NOT berthed)	ARRI
Container Discharged	Container unloaded from the vessel	DISC
Transshipment	Container transferred between vessels at intermediate port	—
Container Gated Out	Container left the destination terminal	GTOT
Container Return / Empty Return	Empty container returned to carrier depot	—

“Vessel Arrival” is the most operationally dangerous label in this table. On most carriers — Maersk, CMA CGM, Hapag-Lloyd — “Vessel Arrival” or “Arrival at POD” means the ship has berthed and discharge operations can begin. On ONE, it means the vessel is at anchor or in the vicinity of the port. The ship has not necessarily berthed. It has not started discharging containers. Visibility platform Vizion explicitly confirms this distinction in its documentation.

The practical impact is significant. A “Vessel Arrival” event on ONE can precede actual berthing by 3 to 48 hours, depending on port congestion and berth availability. If your dispatch team sees “Vessel Arrival” and starts mobilizing a trucker or notifying a consignee, they may be 1-2 days early. The container will not show “Container Discharged” until it is actually off the vessel, and discharge can take another 24-72 hours after berthing. Always wait for the “Container Discharged” event before taking action at the destination.

ONE does publish an “Empty Return” event, which is more than some carriers offer. If you need to confirm that an empty was returned within the free time window, ONE’s portal at least shows you that the event fired — though you will still need the EIR for formal documentation.

Update Cadence: How Fresh Is the Data?

ONE’s tracking data lags by 6-12 hours, with backend systems updating 2-3 times daily. This places ONE in the middle of the pack — slower than Maersk’s 2-8 hours, roughly comparable to CMA CGM’s confirmed 6-12 hour lag.

The enhanced tracking interface does not change the underlying data freshness. The April 2025 redesign improved how the data is displayed — adding the vertical timeline, progress bar, and alerts — but the events themselves still flow through the same backend pipeline with the same synchronization frequency. A prettier interface does not mean faster updates.

The “Vessel Arrival” lag compounds the anchor ambiguity. If a vessel drops anchor at 06:00 and the event does not post until 12:00-18:00, and then berthing takes another 12-24 hours, and then discharge takes another 24-48 hours — you can be looking at a 3-4 day gap between the “Vessel Arrival” event appearing on your screen and the container actually being available at the terminal. Plan accordingly.

Known Gaps and Quirks

The “Vessel Arrival” = anchor problem is the single biggest operational gap. This has been covered above, but it bears repeating because it is the most common source of tracking-related dispatch errors for teams using ONE. If you track across multiple carriers and apply the same logic to “Vessel Arrival” across all of them, you will be early on ONE by hours or days.

Master B/L only — no House B/L support. This is a significant limitation for freight forwarders who issue House B/Ls. To track on ONE’s portal, you need the Master B/L number, which the forwarder may not share with the end shipper or consignee. If you are the beneficial cargo owner and your forwarder has not given you the Master B/L, ask for it specifically — or track by container number instead.

Premier Alliance reliability is the lowest among the three alliances. ONE, HMM, and Yang Ming formed the Premier Alliance effective February 9, 2025, with a five-year term and approximately 340 vessels. The alliance’s schedule reliability sits at roughly 56.9%, compared to Gemini’s 92.3% and the Ocean Alliance’s mid-range performance. This means nearly half of all Premier Alliance sailings deviate from the published schedule.

No “Available for Pickup” event. Like MSC and CMA CGM, ONE does not publish a combined availability event. After “Container Discharged,” you are blind to whether customs has cleared, freight has been released, and the terminal has made the container accessible. Check with your broker and the terminal independently.

Transshipment detail is thin. ONE labels transshipment as a single event rather than breaking it into discharge, dwell, and reload at the hub. For shipments routing through busy Premier Alliance hubs, the gap between the transshipment event and the next leg’s departure can be days without any new tracking data.

What to Do When Tracking Breaks

Scenario 1: “Vessel Arrival” posted but no “Container Discharged” for 48+ hours. This is likely normal. “Vessel Arrival” on ONE means the vessel is near the port, not berthed. Check the vessel’s position on MarineTraffic — if it is still at anchor, discharge has not started. If the vessel is at berth but no discharge event has posted after 48 hours, the event may not have synced yet. Give it another 12-24 hours, then contact ONE.

Scenario 2: House B/L returns no results. ONE does not accept House B/Ls. You need the Master B/L number or the container number. Contact your freight forwarder for the Master B/L if you do not have it.

Scenario 3: Legacy NYK/MOL/K Line container not found. Try the container number with the legacy prefix (NYKU, MOLU, KKFU). If the container has been rebranded with an ONEU number, the legacy prefix will not resolve. Contact ONE customer service for cross-referencing legacy equipment numbers.

Scenario 4: ETA keeps changing on a Premier Alliance routing. With the alliance’s 56.9% reliability, ETA shifts are common. Check whether the vessel name has changed (indicating a connection was rebooked) or whether the same vessel is running behind. If the routing involves a transshipment through a Premier Alliance hub, the feeder connection is where delays compound. Contact ONE for the confirmed feeder details.

Scenario 5: Exception alert fires on the new tracking interface. ONE’s April 2025 enhancement added exception alerts for schedule deviations. If you see a red alert, it means ONE’s system has detected that the shipment has deviated from the planned timeline. Check the associated event details for the specific deviation — it could be a vessel delay, a missed connection, or a terminal hold. The alert is a notification, not a resolution. You still need to take action.

API and Integration Options

ONE’s developer portal at developers.one-line.com exists but its scope is not fully public. Unlike Maersk’s fully self-service portal or CMA CGM’s two-tier offering, ONE’s API documentation is less transparent about what endpoints are available, what data they return, and what the access requirements are. The “get started” page provides initial guidance, but the full API catalog requires engagement with ONE’s team.

ONE is a DCSA founding member and supports Track and Trace v2.2. In February 2025, ONE announced a partnership with GSBN (Global Shipping Business Network) for DCSA-standard electronic bills of lading. This signals ONE’s commitment to the DCSA ecosystem, even if the API itself is not as openly documented as competitors.

For programmatic tracking at scale, the API is the intended path — but expect a less self-service experience than Maersk or Hapag-Lloyd. Plan for some back-and-forth with ONE’s team to get access and understand the available endpoints. Third-party visibility platforms (Vizion, Terminal49, project44) also pull ONE data and may offer a faster path to integration if you do not need direct API access.

Operational Note: The “Vessel Arrival” = anchor distinction is not a footnote — it is the single most important thing to understand about tracking on ONE. If your standard operating procedure treats “Vessel Arrival” as the trigger for downstream action (trucker dispatch, consignee notification, customs filing), that procedure will misfire on ONE shipments. Adjust your SOP to trigger on “Container Discharged” instead, and add 24-48 hours of buffer between the arrival event and any action that depends on the container being physically accessible. For teams managing shipment-level visibility across the Premier Alliance, normalizing ONE’s anchor-based arrival with other carriers’ berth-based arrival is a data engineering requirement, not a nice-to-have.

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