100Mbps Leased Line: Costs, Speeds & Providers Explained

For most SMEs with between 20 and 80 staff, a 100Mbps leased line hits the sweet spot between cost and performance. You get a full 100Mbps in both directions, a dedicated circuit that no other business shares, and a formal service level agreement that holds the provider accountable if things go wrong. It is a fundamentally different product from broadband, and it is worth understanding exactly what you are paying for before you sign a contract.

What Is a 100Mbps Leased Line?

A leased line is a private fibre circuit connecting your premises directly to the carrier's network. Unlike FTTC or FTTP broadband, the bandwidth is not shared with other businesses or residential users. When you order 100Mbps, you get 100Mbps upload and 100Mbps download, consistently, at any time of day.

The connection is described as symmetric because upload and download speeds are identical. This matters enormously for businesses that rely on cloud applications, host their own services, conduct video conferencing or regularly transfer large files to remote sites.

How Much Does a 100Mbps Leased Line Cost?

Pricing depends on three main factors: your postcode (specifically how close you are to existing fibre infrastructure), the provider you choose, and whether you require any additional features such as static IP addresses or enhanced SLAs.

• Central urban locations (major cities, business parks with existing infrastructure): £199–£280/month
• Suburban and semi-rural locations: £280–£380/month
• Rural or hard-to-reach premises: £380–£450/month or higher if significant civil works are needed

These figures are for a standard 36-month contract. Shorter contracts cost more per month; longer 60-month agreements can bring the monthly charge down by 10–15%. Most leased lines also attract a one-off connection fee, which typically ranges from £0 (on promotional deals) to around £1,000 depending on the provider and distance involved.

What Is Included in the Price?

A reputable leased line contract should include the following as standard:

• The physical fibre circuit from your premises to the provider's point of presence
• A customer premises equipment (CPE) router, either purchased or rented
• A block of static IP addresses (usually a /29 or /30)
• A service level agreement covering fault response and repair times
• 24/7 monitoring and proactive fault management

SLAs for leased lines are significantly stronger than those for broadband products. A typical leased line SLA commits to a four-hour engineer response for P1 faults and a maximum mean time to repair of eight hours. Some providers offer even tighter SLAs for a premium.

Installation: What to Expect

A 100Mbps leased line typically takes 60 to 90 working days to install from the point of order. This timeline covers survey, wayleave agreements (permission to lay fibre across third-party land), civil works where required, and final installation and testing. In some locations with pre-existing duct infrastructure, installs can complete in as little as 30 days. In rural areas or where planning permissions are involved, it can take longer.

You will need to appoint a named contact within your business who can liaise with the installation team, confirm access to the building and sign off on the completed works. Your provider should keep you updated throughout the process, though in practice the quality of project management varies considerably between carriers.

100Mbps vs Other Speeds

100Mbps is the most common entry point for leased lines, but it is not the only option. If your team is growing or your workloads are becoming more demanding, it is worth considering whether a larger circuit makes sense from day one.

• 100Mbps: Suitable for 20–80 users with typical cloud workloads (Microsoft 365, Teams, CRM, VoIP)
• 200Mbps: A good middle ground for 50–150 users or where video conferencing is heavy
• 500Mbps: For larger offices or businesses with data-intensive workloads
• 1Gbps: Future-proof choice for large sites, data centre connectivity or multi-site aggregation

The price difference between 100Mbps and 200Mbps is often smaller than businesses expect. It is worth asking your provider to quote both speeds simultaneously so you can make an informed decision.

Is a 100Mbps Leased Line Right for Your Business?

A leased line makes sense when any of the following apply:

• You have 20 or more staff relying on cloud applications simultaneously
• Downtime has a direct cost — for example, in financial services, legal, healthcare or e-commerce
• You host services that external users need to reach (VoIP, VPN, servers)
• You need guaranteed upload speeds for backups, file transfers or video production
• Your FTTC or FTTP broadband has caused recurring problems and your provider cannot resolve them

AMVIA helps businesses compare leased line quotes from multiple carriers across the UK. Rather than dealing with individual providers, we manage the procurement, installation and ongoing relationship on your behalf, so you get the right product at the right price without the complexity.

Key Questions to Ask Before Signing

Before committing to a 100Mbps leased line contract, make sure you have clear answers to the following:

• What is the committed information rate (CIR) — is it 100% or less?
• What are the exact SLA terms, including financial penalties for missed targets?
• Is the CPE router included in the monthly price or rented separately?
• What happens at the end of the contract — does the price change automatically?
• Is there a secondary circuit or failover option available?