GPS Jamming and Spoofing: What Port Suppliers Must Quote

GPS jamming and spoofing are now a routine navigational risk in busy shipping regions, and the UK has told owners to plan for it. For port service providers, that changes what you quote: vessels may arrive with degraded positioning, altered ETAs and extra documentation demands.

The UK Maritime and Coastguard Agency issued MGN 719 (a Marine Guidance Note telling owners and crews how to prepare) warning that satellite navigation can no longer be taken for granted in some of the world’s busiest shipping regions (Splash247, October 2026). A Seatrade Maritime webinar on protecting fleets from GPS attacks notes that jamming and spoofing are rising fast across busy waterways, putting crews, cargo and insurance claims at risk (Seatrade Maritime News, November 2026).

What jamming and spoofing actually do to a port call

Jamming drowns satellite signals with noise; spoofing sends fake signals so a receiver computes a wrong position or time. Research describes spoofing as transmitting a signal that appears authentic but makes the receiver compute an erroneous navigation solution, time, or both (Journal article).

A 2022 study in Mathematics found that GNSS signals are vulnerable to spoofing because of low power and easy access, and proposed detection using receiver integrity monitoring with inertial sensors (Mathematics). For a port agent or chandler, the practical result is uncertainty: the ETA (estimated time of arrival) may shift, the vessel’s reported position may not match the berth, and the master may be managing a navigation problem while you are trying to confirm a delivery window.

Cyber risk is becoming an insurance question

Insurers are moving from questionnaires to products. Hanwha General Insurance and CYTUR have partnered to develop maritime cyber insurance solutions combining vessel cybersecurity assessments, risk monitoring and incident investigation (Marine Insight, October 2026).

That matters to suppliers because cyber incidents increasingly sit alongside traditional P&I (protection and indemnity) cover in a ship manager’s risk review. When a technical superintendent or procurement manager asks whether your team can work with a vessel suffering navigation interference, a clear answer helps you stay on the approved supplier list.

Emissions data standards add a second documentation layer

The BIMCO-led JIWG has released version 1.0 of the OVD and VER frameworks to standardise vessel data exchange and reduce duplicate emissions reporting (Marine Insight, October 2026). OVD and VER are common data formats for vessel and emissions reporting.

For bunker suppliers, this reinforces a trend already visible in the Bunker Delivery Note: the document is no longer just a receipt, it feeds compliance reporting. Our guide to bunker delivery note requirements for emissions reporting sets out what to keep ready before the barge arrives.

Security incidents in the Gulf raise the stakes on timing

A tanker caught fire in Hormuz after explosives were attached to its hull, in what Seatrade describes as a new modus operandi by Iran against commercial shipping (Seatrade Maritime News, October 2026).

Attacks and navigation interference share one commercial effect: they make vessel schedules less predictable. Suppliers who can respond to a changed ETA with a revised quote, a revised delivery slot and a clear record of what was agreed will keep the work. Our playbook on re-quoting a bunker quotation after an ETA change applies equally to chandlers and agents.

What this means commercially for maritime service providers

• Chandlers: build a fallback contact route when a vessel’s ETA is unreliable. Confirm the delivery window with the agent and the chief officer, not only with the AIS (Automatic Identification System, which broadcasts a ship’s position and identity) arrival prediction.
• Bunker suppliers: treat a spoofed or jammed ETA as a re-quote trigger. Check credit before you re-fix a stem, as set out in our guide to a bunker supplier credit check before re-quoting a stem.
• Port agents: keep a written record of every ETA change and who confirmed it. Cyber-related delays may end up in a claim, and clear notes protect you.
• Repair yards and marine service companies: if a vessel arrives with navigation equipment faults, expect inspection and reporting work alongside the original job. Offer a documented handover to the superintendent.

A practical response checklist

1. Add a GPS-interference question to your pre-arrival email: has the vessel experienced jamming or spoofing on this leg?
2. Record the source of every ETA update: agent, master, AIS or port authority.
3. Keep a cyber-incident contact at the ship manager alongside the technical superintendent.
4. Review your documentation for emissions-linked deliveries against the new OVD and VER formats.

How VesselReach helps

VesselReach turns vessel movements at your target ports into conversations with the people who decide. When schedules shift, that matters more than ever.

• Vessel intelligence: see vessels near your ports and scheduled arrivals, so you can contact decision-makers before the vessel berths.
• Decision-maker discovery: find operations, procurement and technical superintendents by role, so a changed ETA reaches the person who can confirm it.
• Multichannel outreach with follow-ups: email, WhatsApp and phone, with automated follow-ups when there is no reply.

Book a VesselReach demo to see how it works on your ports; a 10-day free trial is offered after the demo meeting.