Inshore vessel monitoring systems (iVMS): guidance

Inshore vessel monitoring systems (iVMS) are installed on fishing vessels and transmit information to the fisheries authority. This includes the geographical position, date, time, speed and course of the vessel.

Legislation came in to force on 15 February 2022 and requires the use of VMS on all licensed under 12m fishing vessels that operate in Welsh Waters, and Welsh vessels wherever they are fishing. It is an offence to fish without a functioning iVMS device on your vessel and enforcement action could be taken.

iVMS devices must provide the following information to Welsh Government (via the UK VMS Hub) at least once in every 10 minutes:

• the most recent geographical position of that boat using coordinates of latitude and longitude on the World Geodetic System 1984, with a position error of less than 10 metres
• the date and time expressed in Co-ordinated Universal Time of any geographical position of that boat
• the speed and course of that boat at that time

iVMS shows us when and where fishing activity is taking place. This helps us to gain a better understanding of the scale, location and seasonality of fishing activity and aid fisheries management.

In 2019 we introduced Catch Recording for under 10m vessels. This provides us with more information about what is being caught in Welsh waters. Combining catch data with iVMS gives us a fuller picture of fishing effort and helps us to manage fishing sustainability.

iVMS provides the industry with evidence of their catch origin and fishing grounds. This could be used to resolve conflicts with other marine users and for responding to marine planning and licensing consultations.

The introduction of iVMS creates a common requirement for all UK and third country under 12 metre vessels fishing in Welsh waters and enables enforcement to operate in a more efficient and targeted manner.

In August 2025 Welsh Government became aware that Succorfish Inshore Vessel Monitoring System (iVMS) devices were no longer transmitting data to the UK VMS Hub in accordance with statutory requirements. We advised that until further notice, those using Succorfish devices should continue to operate as normal, including having their iVMS devices switched on and transmitting positional data while at sea. 

This decision reflected the expectation that the interruption in data transmission would be temporary, however, several months have now passed with no resolution.

Effective 31 March 2026, Succorfish devices that do not transmit timely data to the UK VMS Hub will no longer be recognised as compliant with The Sea Fishing Operations (Monitoring Devices) (Wales) Order 2022 regulations. 

You may wish to check the Marine Management Organisation approved devices list to identify alternative device suppliers. Currently Fulcrum/CLS is listed.

If you are interested in a device that isn’t on the Marine Management Organisation approved devices list or approved by another UK Fisheries Authority you will need to contact us to discuss whether the device is suitable. The device must be able to transmit to the UK VMS hub, any device not already approved by UK authorities may incur additional connection charges.

We are currently piloting a new iVMS device supplied by Rewire and are seeking additional volunteers. The number of participants is limited, with priority given to those who currently use a Succorfish device. A Rewire iVMS will be provided free of charge, but installation costs are not covered (as the devices require hard wiring), and vessel owners will be responsible for paying airtime directly to Rewire. Taking part in the Rewire pilot study is considered to meet iVMS regulatory requirements, and participation will last for one year, ending in March 2027. 

If you would like to take part in the pilot study or have any questions, please contact:

• email: MarineEvidenceandTech@gov.wales
• phone: 03000 258907 or 03000 258923