Q1
Best network for UB9?
O2 leads with 100/100 — driven by 100% 5G and 100% 4G in this densely populated urban part of Southall.
UB9 DISTRICT · BUCKINGHAMSHIRE
Best mobile network in Harefield UB9 · Buckinghamshire
O2 scores 100/100 — the best measured network for UB9 in Southall, 12 points clear of the weakest. 100% 5G-grade · 100% 4G. Ofcom Mobile Coverage data (May 2025), measured across 96 addresses in 6 sampled postcodes.
The UB9 district covers Harefield, Denham, Gerrards Cross and Ruislip, in Buckinghamshire. Signal varies street by street — scan your exact postcode below.
RESULT · UB9 · SOUTHALL
Coverage for UB9 district
★ BEST MEASURED
O2
100/100
O2 has the strongest measured coverage for the UB9 district in Southall, 12 points clear of the weakest network in Ofcom's data.
Full ranking — UB9
#1
O2
#2
Vodafone
#3
Three
#4
EE
Coverage analysis — UB9
Drawing on Ofcom's sampled address-level coverage, O2 comes out on top for Southall. In this densely populated urban area, O2 achieves an overall coverage score of 100/100 — driven by excellent 5G coverage (100%) and rock-solid 4G at 100%. 5G and 4G scores are closely matched, reflecting a mature, stable network.
O2 comfortably leads Vodafone by 0 points overall. While Vodafone reaches 100% on 5G and 100% on 4G in Southall, it falls short of O2's combined performance across all bands. Three and EE round out the field at 99 and 88 respectively.
Why O2 for UB9?
O2's 5G rollout in Southall is among the strongest nationally, covering 100% of premises in the UB9 district. For anyone streaming video, gaming on mobile, or relying on a mobile hotspot at home, this level of 5G penetration makes a real difference to day-to-day speed.
The runner-up in UB9 is Vodafone at 100/100 (100% 5G / 100% 4G). It is a close contest — both operators deliver strong coverage in UB9, and your choice may come down to tariff, handset preference, or existing contract.
Switching to O2 in Harefield
O2 has the strongest measured signal here — 100/100, with 100% 5G-grade and 100% 4G coverage across Harefield, Denham, Gerrards Cross and Ruislip, 12 points clear of the weakest. A cheaper plan on a network that does not reach your street costs more than it saves, so start from the coverage and pick the plan second.
Some links on this page are affiliate links. If you switch through one we may be paid a commission. It never changes which network we rank first - that comes from Ofcom coverage data alone.
Explore the Southall area
View full coverage analysis for the Southall (UB) area, or enter any UK postcode in the scanner above for a personalised result.
Coverage FAQ — UB9
Q2
Is 5G available in UB9?
O2 provides excellent 5G coverage at 100%. Vodafone follows at 100%.
Q3
Which network has the best 4G?
O2 leads 4G too at 100%. Reliable 4G is critical in densely populated urban areas.
Q4
Is Three worth considering?
Three scores 99/100 in UB9 (100% 5G, 100% 4G). It may suit certain tariff or price preferences despite trailing the top two.