Identifying vessels of interest using the past ports filter

This article is Level 6 in the Filtering training series →

Understanding where and when a vessel has visited a port can help to assess a vessel’s risk. Starboard’s port filters are a powerful tool that enables analysts to conduct a range of tasks, including vessel risk identification, fleet analysis, long term trend analysis, operational dashboards, and statistical reports.

Past ports visits filters can be found by clicking + Add Filter in your toolbar.

The simplest port filter to start with is the Last port of call. You can use this filter by selecting + Add Filter, Past port visits, and then Last port of call. This filter applies to a vessel’s last port relevant to their current journey, which will also default to the vessel’s current port if it is not at sea at the time.

Try it out: See vessels that have entered the NZ EEZ (but not a NZ port) between 1-17 October 2025, whose last port of call was Australia.

The example image above demonstrates this filter by applying the following:

This filter returns vessels that entered the NZ EEZ between 1–17 October 2025 and whose last port of call was Australia. Vessels currently within a NZ (or other) port are excluded, as their current location becomes their new last port of call. In other words, the results show vessels that departed from Australia, entered the NZ EEZ during the specified period, and remained at sea without yet entering another port.

The Last port of call filter can also be used to exclude specific territories. To do this, change the dropdown option from “Was IN ANY of the following territories” to “Was NOT IN ANY of the following territories”, then select your territories of interest and click Done. In this mode, vessels whose last port of call was in the selected territories will be excluded from the results.

The second type of port filter is the Past Ports filter, which is accessed through the same menu. This filter ignores a vessel’s current port and any intermediate ports outside your territory(s) of interest. In practice, this allows you to identify vessels that have visited a specific port within a defined timeframe, regardless of where they have travelled in between.

You can choose from four date ranges for this filter, where vessels “have visited during the previous” 7 days, 30 days, 90 days, or year (previous 365 days). When you select a past time range in the filter menu, the system will automatically generate (at the bottom of the Past port visits filter) the exact date range that the filter will apply to once activated.

It is important to understand that when using the Past Ports filter, two separate time filters are applied:

Understanding this distinction is crucial, as applying the filters incorrectly can skew your analysis and lead to misinterpreted results.

Try it out: See the vessels which have been within the NZ EEZ in the last 7 days, who have also used an Australian port in the last year.

Mastering the Past Ports filter unlocks a range of capabilities that can significantly enhance your analysis, including the identification of complex operating patterns among high-risk vessels. Consider the following example:

This approach helps to uncover tanker vessels that have entered the NZ EEZ during a set-time frame, while also having entered a Russian or Indian port in the previous 90 days, regardless of the ports they've visited in between.

Try it out: See the results of filtering on Vessel type: Tanker, Area: NZ EEZ, and Past ports: Any Russian or Indian port in the previous 90 days.

You can also reverse-engineer the Past Ports filter to focus on specific ports of interest, rather than all ports within a selected territory. To do this, first identify your chosen port by enabling the “Port Boundaries” layer, located under Map Layers → Area Layers. Then, zoom in until the port boundary is fully visible on your screen, and ensure your Area filter is set to “On Screen”.

Alternatively, you can create a custom area around your specific port (or area) of interest, and filter on that instead of “On screen”.

Once you have isolated your specific port (or custom area) of interest, you can apply any additional filters related to vessel characteristics or activities, followed by a Past Ports filter targeting your destination(s) of interest.

This is where the reverse-engineering effect comes in, as you can use this function to assess (for example):

Try it out: See Tanker vessels that have visited Indian oil-transfer anchorages (on screen) in the last year, while also having visited a NZ port in the last 7 days.

This works because the Past ports filter is not chronologically bound, but rather highlights vessels that have been in two specific places during a window of time.

The next example shows a more advanced use-case, looking at sensitive cable areas near large coastal cities. Here, we zoom in to a custom area made for a apply a complex range of filters for specific vessel activities and characteristics, and then use the Past Ports filter to identify connections with other territories of interest over the past 90 days.

This filter process reduces ~3,000 vessels passing through the cable area, to just 8 highly suspicious vessels that meet the sabotage criteria.

The next example demonstrates a more advanced use case, focusing on sensitive cable areas near major coastal cities. In this scenario, we choose a custom area created for a cable sabotage location near Taiwan. Several filters for specific vessel activities and characteristics have been applied with the Past Ports filter in order to isolate connections between the custom area and other territories of interest over the past 90 days.

Through this filtering process, ~3,000 vessels passing through the cable area are narrowed down to just eight suspicious vessels that meet the defined sabotage criteria.

Try it out: See these 8 suspicious cargo vessels that have loitered in both the Taiwan cable area and ports of China or Russia at some point within the past 90 days.

In addition to analysing operating patterns, the Past Ports filter enables you to compile and automate dynamic statistical reports for trend analysis and anomaly detection within your area of interest. For example, you can generate daily, weekly, monthly, quarterly, or annual reports that show how different types of vessels have used your country’s ports over time. These long-term trends can serve as a baseline to quickly identify anomalies and outliers in real time, helping you prioritise inspections. The raw data can be exported from the Vessel list feature and integrated with Business Intelligence tools such as Power BI to create interactive dashboards that support common operating pictures, policy briefs, intelligence reports, and more.

For help creating dashboards from Starboard data, contact our team! support@starboard.nz

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