Do You Need to Register an Underwater Drone in the UK?

Why the CAA Does Not Regulate Underwater Drones

The Civil Aviation Authority (CAA) regulates unmanned aircraft — devices that fly in UK airspace. The legal basis for drone regulation comes from the Air Navigation Order 2016 (ANO), which defines an unmanned aircraft as any aircraft operating without a pilot on board.

An underwater drone, also known as a remotely operated vehicle (ROV), does not fly. It operates beneath the water surface. Because it never enters airspace, the ANO does not apply. This means:

• No Flyer ID is required
• No Operator ID is required
• No registration on register-drones.caa.co.uk is needed
• The Drone and Model Aircraft Code does not apply
• No altitude or distance restrictions under CAA rules

Popular consumer ROVs such as the Chasing Dory, FIFISH V6, and PowerVision PowerRay are submersible devices, not aircraft. They fall entirely outside CAA jurisdiction.

What About Hybrid Air-and-Water Drones?

Some newer drones can both fly through the air and dive underwater. If your device is capable of aerial flight — even if you primarily use it underwater — the aerial portion of its operation is covered by CAA rules.

For a hybrid drone that flies and dives, you would need to follow standard UK drone regulations during any airborne phase. This includes obtaining a Flyer ID, potentially an Operator ID (depending on weight), and following all airspace restrictions. Once the device is submerged, the CAA rules no longer apply to that portion of the flight.

If you are unsure whether your device qualifies as an aircraft, check whether it has propellers or rotors designed for aerial lift. If it does, treat it as a flying drone for registration purposes.

Maritime Rules That Apply to Underwater Drones

While the CAA does not regulate underwater drones, other regulatory frameworks do apply depending on where and how you operate:

Navigation and Safety

If you are operating an ROV in navigable waters — harbours, shipping lanes, rivers, or coastal areas — you must be aware of maritime navigation rules. The Marine and Coastguard Agency (MCA) oversees safety on UK waters. Local harbour and port authorities may have their own bylaws restricting or requiring permission for ROV operations in their jurisdiction.

Environmental Protection

Marine protected areas, Sites of Special Scientific Interest (SSSIs), and Marine Conservation Zones (MCZs) may have restrictions on what equipment you can deploy underwater. Disturbing protected marine habitats or species could lead to enforcement action under environmental legislation.

Diving and Access

Some locations require landowner permission or specific access rights to launch an underwater drone. Private lakes, reservoirs, and some stretches of river are not open for public use of ROVs without consent.

Data Protection and Recording Laws

Many underwater drones are equipped with cameras. Even though CAA rules do not apply, the UK General Data Protection Regulation (UK GDPR) and the Data Protection Act 2018 still do.

If your recordings capture identifiable individuals — for example, divers, swimmers, or people on boats — you have obligations under data protection law. For personal and recreational use, a household exemption generally applies. For commercial or research purposes, you may need to consider data protection impact assessments and ensure lawful processing of any personal data.

Recording in certain areas, such as military installations or restricted sites, may also raise security concerns regardless of whether the device is airborne or submerged.

Commercial Use of Underwater Drones

Using an ROV commercially — for underwater inspections, marine surveys, search and recovery, or film production — does not trigger CAA regulations. However, you may need:

• Public liability insurance appropriate for marine operations
• Risk assessments for the specific operating environment
• Permission from harbour authorities, marina operators, or landowners
• Compliance with Health and Safety at Work Act 1974 if operating as a business
• Professional indemnity cover depending on the nature of contracted work

There is no CAA operational authorisation (such as a GVC or PfCO equivalent) required for underwater-only drone operations.

Summary: What You Need and What You Do Not

For a purely underwater drone (ROV) in the UK:

• CAA registration: Not required
• Flyer ID: Not required
• Operator ID: Not required
• Drone Code: Does not apply
• Maritime awareness: Required — check local port and harbour rules
• UK GDPR compliance: Required if recording people
• Environmental rules: Required in protected marine areas
• Insurance: Strongly recommended, especially for commercial use

If your device can also fly, standard CAA drone rules apply during any aerial phase. For registration guidance on flying drones, see our complete UK drone registration guide.