top of page

Join us on the app

AIS, Port Calls and Other Methods - What is Vessel Tracking Data?

Updated: Mar 21, 2023

Ship tracking is a highly valuable dataset that provides insights into trade, supply chains and shipping movements at global and regional levels.

Ship tracking truly is big data with daily files covering the global fleet sometimes exceeding 400m data points a day.

Image by fanjianhua on Freepik

What is Vessel tracking data and where does it come from?

Ship tracking, also known as vessel monitoring, is the process of monitoring the position of a ship in real time, at a chosen interval, or looking back over its historical voyages.

There are multiple means to track vessels, the most common being AIS.

Automatic identification system (AIS) is Ship tracking system whereby transponders on ships relay information on their location, speed and course (full message details below) to other ships and to shore.

The information contained within an AIS message can be broken down into 3 categories:

Static information:

  • Identity

  • IMO number

  • Length and beam

  • Vessel type

  • Location of position-fixing antenna

Dynamic information:

  • Position

  • Speed over ground

  • Course over ground

  • Navigational status

  • Rate of turn

Voyage information:

  • Type of cargo

  • Destination

  • Estimated Time of Arrival (ETA)

  • Route plan

  • Safety-related information

There are 3 sources of AIS Data:

Terrestrial AIS: Land based receivers that can record high volumes of data at short ranges (typically up to 50 miles).

Satellite AIS: Satellite based receivers that can record lower volumes of data but at significantly longer ranges, typically utilized when the user requires positional data outside the reach of land-based receivers (think deep sea transits).

Shipborne AIS: Ship based receivers which can support users to gather data in high traffic zones where the effectiveness of terrestrial and satellite AIS is compromised due to busy communication channels.

Other sources:

Long-Range Identification and Tracking:

The Long-Range Identification and Tracking (LRIT) system provides for the global identification and tracking of ships to enhance security of shipping and for the purposes of safety and marine environment protection.

LRIT information is provided to Contracting Governments to the 1974 SOLAS Convention and Search and rescue services entitled to receive the information.

Port agents:

Networks of agents of used to manually collect data on ship arrivals, sailings and other data points.

Relied on heavily before the widespread application of AIS, port agents can provide unique coverage in areas of congestion and where AIS receivers are difficult to place and/or maintain.

Satellite imagery:

Images recorded by satellite that provide a lower cadence but often more detailed view on the position of a ship and its activities.

Sat imagery is used in combination with AIS to help companies and governments detect illicit behaviour.

How can I use it?

Monitoring fleet positions

  • Where is your fleet and the fleet of your competitors?


  • Where are you current/future operating?

  • What is the likehood they are engaged in illicit trade?

Business development

  • Which ships are approaching the port you operate in?

Supply and demand analysis

  • What is the supply of competing vessels in an area and assessing the impact on freight rates

  • What is the current and future supply of cargo vs demand in region compared to historical norms?

  • Drawing relationships between shipping activity and price action

Macroeconomic analysis

  • Arrivals and sailings per country + utilization rates

How do I access the data?

Platforms and data feeds.


Ship tracking platforms range from free > freemium > premium and can support a range of different use cases and budgets.

Typically platforms augment AIS data with some form of vessel and ownership data in order to show the user what sort of ship they are viewing and who owns and/or operates it.

Other organizations, that we would consider in the premium category, have deeper and wider ranging databases (ports, vessel incidents, cargo etc) that support them to derive additional datapoints such as risk indicators (think insurance, chartering, vetting and compliance) as well cargo volumes and predictive insights.

Data feeds:

Various suppliers provide direct data feeds, either proprietary or resold.

The benefit or going with a supplier of proprietary data is they tend to have more control over quality assurance and uptime vs resellers who have to resolve issues via a 3rd party whereas resellers often add value through aggregation or augmentation.

These feeds are typically delivered via API or FTP.

  • API - the delivery mechanism can often be as important as the product it is delivering.

  • FTP/S3 Bucket - a less dynamic but effective way of delivering large data files.

Take the time to speak to the Data Services/Delivery teams to understand the mechanics of their APIs as well as their record of maintaining them i.e uptime and error management.

How to assess one AIS supplier vs another?

Basic framework:

Coverage - how many unique vessels do they track?

  • You can use unique identifiers such as the vessels *MMSI number* to help compare products

Frequency - how often are they recording a new position on those vessels?

  • Look for the "date time stamp" to help establish which messages are new vs old

Accuracy - number of duplicate + erroneous messages / total messages

  • An example of an erroneous message could be a vessel traveling over a mass of land or message series suggesting the ship is operating at speeds far beyond its capabilities.

Is there a cost to use the data?


There are several free platforms that provide good but limited functionality.

Users can typically see the last recorded position and port call + basic vessel data fields with the option to upgrade to see additional data points and histories.

It’s also possible to obtain free historical information for the US coast from NOAA office for coastal management at their FTP site.

Only some of these suppliers will be able to offer data feeds. This will depend on whether they own and operate their own networks of AIS receivers and/or their license agreements with other proprietary suppliers.

Paid for:

By no means are vessel tracking systems all the same.

AIS is often referred to as a ‘commoditized’ offering insinuating parity across the various supplier when it comes to coverage, accuracy and frequency.

Paid for services are usually either the proprietors of their tracking data + have created integrated feeds combing terrestrial, satellite and other supporting sources.

This results in:

  • More vessels

  • More positions

  • More accurate records

Other paid for platforms are built to support particular use cases:

  • Maritime compliance

  • Cargo tracking

  • Vessel performance

Data is offered in the following formats:

  • One-time deliveries

  • Ongoing feeds - typically 12-month contracts

  • Pay as you go - less widely available


Since the commercialisation of AIS, ship tracking data has become a near enough essential source of information to most (if not all) market participants in maritime.

From staying competitive to remaining compliant, it is integral to operating effectively and perhaps more importantly, within the confines of the law.

It acts as a platform for an entire ecosystem of innovative software providers to build sophisticated tools that support users to understand global trade flows, maritime domain awareness and compliance risks.

That being said and like with most maritime data sets, there is a spectrum.

While free/freemium sources of data, be that via feeds or platforms, are great for performing straight forward and low risk tasks, they often can't provide the necessary coverage, frequency and accuracy to effectively support more complex use cases.

A trader with access to updated ship positions every 24 hours may well outcompeted by those with real time positions who can detect voyage deviations (and in turn changes to supply and demand forecasts) far earlier.

Do not overlook delivery. A supplier may test incredibly well against your evaluation criteria however if they do not have a reliable means by which to supply, that becomes less important.

We hope this article has been helpful in understanding what ship tracking data is, where it comes from, how it's used and how to access it.

For more information on ship tracking and other maritime data and applications, reach out for free support.


bottom of page