CB21 broadband and area guide
Ofcom coverage, connection speeds, house prices and local data for 434 postcodes across 3 sectors in South Cambridgeshire.
Full fibre
0%
Gigabit
55%
Superfast
93%
Postcodes
434
CB21 serves South Cambridgeshire with 93.2% superfast reach and 55% gigabit penetration. This postcode area shows more mixed infrastructure than inner Cambridge.
Broadband speeds in CB21
Share of CB21 premises by the fastest download speed available, averaged across all 434 postcodes in the district.
CB21 extends the Cambridge commuter belt into South Cambridgeshire, with correspondingly more varied infrastructure. Gigabit reaches 55% of the 434 postcodes surveyed, with superfast covering 93.2%. Below-USO premises account for 0.4%, and 1.7% record sub-10 Mbps speeds. The speed split reflects suburban sprawl patterns: 55% gigabit, 38.2% superfast (30-299 Mbps), 1.7% below 10 Mbps. Modern fibre networks have reached most suburbs and commuter areas. Gigabit remains selective, concentrated in newer developments and town centres. Most households have adequate superfast connectivity available.
Source: Ofcom Connected Nations. Percentages are district-wide averages of postcode-level availability, so rows may not sum to exactly 100%.
Connectivity in detail
Below 10 Mbps USO
<1%
Premises unable to get the 10 Mbps universal service minimum
Fixed wireless
0%
Premises that can use a fixed wireless access service
Broadband by sector
CB21 splits into 3 postcode sectors. Coverage and prices can differ street by street, so open a sector below to find your exact postcode.
| Sector | Postcodes | Superfast | Full fibre | Gigabit |
|---|---|---|---|---|
| CB21 4 | 234 | 95% | 0% | 49% |
| CB21 5 | 144 | 96% | 0% | 66% |
| CB21 6 | 56 | 77% | 0% | 49% |
All CB21 4 postcodes (234)
All CB21 5 postcodes (144)
All CB21 6 postcodes (56)
Best deals
Compare broadband deals in CB21
Deals are priced per address. Enter your full postcode to see every package available where you live.
Free comparison. Opens our deals partner in a new tab.
Living in South Cambridgeshire
The 55% gigabit penetration is lower than Cambridge's city postcodes, reflecting suburban development patterns and older residential areas served by superfast copper or older cable.
Remote worker score
54/100
Connectivity and amenities for home working
Family score
50/100
Schools, safety and family amenities
Value score
50/100
What you get for the local price level
CB21 broadband FAQs
Why does CB21 have lower gigabit than Cambridge city?
55% gigabit reflects suburban and older residential areas. Fibre reaches most, but gigabit is concentrated in newer developments.
Is superfast adequate for most households in CB21?
Yes. 38.2% have superfast speeds (30-299 Mbps), which suit typical household use.
Should a remote worker prioritise gigabit in this postcode?
Worth checking. 55% have gigabit available, but 45% are limited to superfast.
Are connectivity gaps common in South Cambridgeshire?
No. Only 0.4% fall below USO minimums, so infrastructure is broadly adequate.
Neighbouring districts
Check your exact postcode
Every postcode in CB21 has its own page with broadband speeds, house prices, school ratings and crime stats. You can also compare providers for your address.
Data sources: Broadband data from Ofcom Connected Nations 2025 · House prices from HM Land Registry · Crime from Police.uk · See all data sources