What is an altnet? Independent fibre explained

Who owns the cable to your home decides which providers can sell to you.

• Openreach is a legally separate, independently governed subsidiary of BT Group. It looks after the copper and fibre lines that connect homes and businesses, and says it sells the same products at the same prices to more than 690 communications providers. Our guide to what Openreach is covers how that works.
• Virgin Media runs its own network, separate from Openreach. Its older hybrid network runs fibre to street cabinets and coaxial cable to the home; its full-fibre network runs fibre all the way. A sister company, nexfibre, builds full fibre too. ISPreview describes it as an open-access network, but Virgin Media and giffgaff, which share some of its owners, are currently the only major providers selling over it. See our guide to Virgin Media's network for more.
• Altnets lay their own fibre cables. They don't always dig new trenches: Openreach rents space in its underground ducts and on its poles to other builders through a scheme called Physical Infrastructure Access (PIA). Airband, for example, says it often runs its own fibre through Openreach ducts. The fibre is the altnet's own even when the duct isn't.

So an altnet is a genuinely separate network, not a reseller of Openreach lines.

The company that owns the fibre isn't always the one you sign up with. There are roughly four set-ups.

Every connection to the internet needs an address. The older system, IPv4, has run out, and buying addresses is expensive. Newer networks without a large stock of their own sometimes use CGNAT (carrier-grade network address translation), which lets many customers share one public IPv4 address.

ISPreview explains that most ordinary users won't notice. It mainly affects:

• online gamers;
• people who need to reach something at home from outside, such as a home server, a CCTV recorder or remote desktop;
• people with particular IT or security requirements.

Bigger, established providers mostly hold plenty of IPv4 addresses, so it's less of an issue with them. Things that reduce the problem:

• IPv6, the newer addressing system, which has addresses to spare. ISPreview says IPv6 support reduces CGNAT's downsides. On a wholesale network, IPv6 depends on the provider you buy from, not the network.
• A static IP address, a fixed public address of your own, sometimes sold as an add-on. YouFibre and Trooli, for example, both list a static IP add-on.

ISPreview found that most altnets don't explain their CGNAT or IPv6 position clearly, and that it can differ between packages. It reported in April 2026 that FullFibre Ltd (the network behind Zzoomm) was using CGNAT to share IPv4 addresses, and said its network fully supports IPv6.

If this applies to you, ask three questions before you order: do you use CGNAT on this package, do you support IPv6, and can I buy a static IP? Our guide to CGNAT, static IPs and IPv6 explains what each answer means.

Since 12 September 2024, Ofcom's One Touch Switch process has worked between physically separate networks, for example from Openreach to CityFibre or Virgin Media. You contact the new provider only; it arranges the switch, your old service ends automatically once the new one is working, and any loss of service mustn't last longer than one working day. If you arrange your own overlap instead, you're outside One Touch Switch and need to cancel the old service yourself.

In practice, not every altnet's own advice matches this yet. Connect Fibre's support page, for example, says that because it has built its own network, your old service isn't automatically cancelled once you're connected; you have to contact your old provider to cancel, and it recommends doing that only after its service is up and running. So when you order, ask the new provider directly: "Will you switch me using One Touch Switch, or do I need to cancel my old provider myself?" Whatever the answer, don't cancel anything until the new line is installed and working.

Other practical differences from switching between two Openreach providers:

• Expect an installation visit. If the altnet hasn't connected your home before, its fibre has to be brought in and a box fitted inside. Community Fibre, for instance, says professional installation is required and usually takes up to two hours. Our guide to full fibre installation covers what happens on the day.
• Pre-ordering is sometimes possible. Connect Fibre takes pre-orders in some areas a few months ahead, with no charge until installation. Hyperoptic lets you register interest in your building, but says registering doesn't guarantee service.
• Check your current contract end date before you commit, so you know whether you'd pay an early exit charge. Under One Touch Switch the new provider should tell you this.

If you're in the countryside and an altnet hasn't reached you, our guide to rural broadband options covers what else is available.

The altnet market is consolidating. ISPreview says high interest rates, rising build costs and competition for the same streets ("overbuild") make it hard for altnets to raise money and grow. It noted in December 2025 that many observers expect the 80 or so altnets of the time to end up as a handful of larger players.

Some deals from ISPreview's consolidation tracker and company announcements show the pattern:

• December 2021: Swish Fibre bought People's Fibre for £2.8m after People's Fibre went into administration.
• June 2024: Netomnia and Brsk agreed to merge.
• January 2025: Zzoomm was brought together with FullFibre Ltd.
• April 2026: Truespeed and Freedom Fibre completed their merger.

In September 2026 ISPreview reported that many altnets had slowed or stopped building to focus on signing up customers, and that Gigaclear's creditors had taken control of the business. The biggest deal pending is nexfibre's £2bn purchase of Netomnia, the network behind YouFibre. Under the plan, the retail business that includes YouFibre (around 500,000 customers) would go to Virgin Media O2. On 2 October 2026 the Competition and Markets Authority (CMA) published provisional findings that the deal would substantially lessen competition in wholesale broadband. ISPreview reported that remedies proposals were due by 16 October 2026 and that the CMA's statutory deadline for a final decision is 15 December 2026. No final decision had been made at the time of writing (9 October 2026).

Because altnet coverage is street by street, check your own postcode. The comparison on our deals pages shows live deals at your postcode from the providers our comparison partner covers, so you can see altnet and national offers side by side.

If you already know which altnet is building near you, our provider pages explain how each works, for example Community Fibre, Hyperoptic, YouFibre, Gigaclear and Zzoomm. You can also browse broadband deals by area for your town. No comparison covers every small provider, so if a local network you've heard of doesn't appear, check its own website as well.

We compare deals through a partner: we don't switch you ourselves, publish our own reviews or give personal financial advice.