Some static indoor mobile repeaters are licence-exempt, but only if the equipment meets Ofcom’s technical requirements.
It is not correct to say that every mobile signal booster is illegal, and it is equally unsafe to assume that any device sold online is lawful. Ofcom permits specified classes of static indoor repeaters that meet defined requirements, including provider-specific and compliant multi-operator models.
What to check before buying
- The seller clearly identifies the device as compliant with current UK requirements.
- The repeater is intended for static indoor use, not for a vehicle or improvised outdoor installation.
- The supported frequency bands match the network service available outside the property.
- There is a usable outdoor signal to repeat.
- The device has automatic controls designed to prevent harmful interference.
Warning signs
- Claims that one unit boosts every band everywhere without installation constraints.
- No UK conformity or technical documentation.
- Manual gain controls presented as a way to overpower nearby networks.
- Instructions to mount an unapproved unit in a vehicle.
- A seller who treats Ofcom rules as optional.
Alternatives to consider first
Wi‑Fi Calling is usually simpler where reliable broadband exists. A different mobile network may also work better because mast locations and radio bands differ. A compliant repeater is most useful where the outdoor signal is adequate but the building blocks it indoors.
Installation still matters
Even compliant equipment can perform badly if the donor antenna points at a weak or unsuitable signal, the indoor and outdoor antennas feed back into each other, or cables introduce excessive loss. Follow the approved installation instructions and stop using the unit if it causes instability. Do not assume that increasing gain is harmless or that a more powerful product is automatically better.
A safer way to make the decision
Do not judge legality from a marketplace title or CE/UKCA marking alone. Check the exact product against current Ofcom repeater requirements and confirm that it is intended for the required UK networks and bands. Stop using equipment that causes interference or behaves unpredictably.
- Prefer Wi‑Fi Calling or a different network where they solve the problem.
- Keep the model and compliance documentation.
- Never use a high-power or outdoor relay not authorised for the installation.
Official sources
Facts checked: 25 July 2026. Network features, device menus and coverage can change. Recheck your exact phone model, software version, network and plan before relying on a feature.
