The Open Championship
Royal Portrush 2025
Golf’s oldest major returned to the Antrim coast in July 2025, drawing roughly 250,000 spectators across the week to a championship links course in a town with a resident population of around 6,500. NetworkUX surveyed the venue on Saturday 19 July, the third championship round. Mobile signal was plentiful across the course — three of the four UK networks ran widespread 5G NSA. Mobile service was a different story.
- Venue
- Royal Portrush GC, Co. Antrim
- Town population
- ~6,500
- Event attendance
- ~250,000 across the week
- Survey day
- Sat 19 Jul 2025 (Round 3)
- Networks surveyed
- Vodafone · EE · VMO2 · Three
Signal isn’t service.
Every network that surveyed had a temporary cell tower in the venue, and three of the four (Vodafone, EE, VMO2) ran widespread 5G NSA across the course. Look only at the signal maps and you’d conclude the networks performed well. Look at the throughput tests and a different picture emerges — only Vodafone delivered usable mobile data at scale, and Three failed almost completely despite 4G signal nearly everywhere.
The gap between “reachable” and “usable”.
For each operator, the top bar shows the percentage of measurements that registered any mobile signal (5G NSA, 4G or 2G). The bottom bar shows the percentage of throughput tests that delivered usable data, defined as 5 Mbps or better. The gap between the two is the story.
Three’s gap is the most extreme — 99.1% signal present, 0% usable data. EE and VMO2 sit close behind. Vodafone is the only operator where signal coverage and usable throughput are even partially in agreement.
Even the “best” was slow. Three was off the charts low.
Average download and upload speed per operator during the survey round. Vodafone delivered roughly four times the throughput of EE and VMO2 — and roughly four hundred times that of Three.
Even Vodafone’s 4.7 Mbps download average is below what users typically expect from 5G NSA in an uncongested area — but it’s a different universe to Three’s 0.01 Mbps. Uploads collapsed on every network, with Vodafone again the only one staying above 3 Mbps.
One network functioning, three networks largely failing.
Each row shows the percentage of throughput tests per operator falling into each quality band. Vodafone is the only operator that delivered more than 10% of its tests at 5+ Mbps.
Same survey routes. Same crowd. Different stories.
Each row below shows two maps for the same operator at the same time: the signal map (which technology and how strong) on the left, and the performance map (how much data actually moved) on the right. A green signal map paired with a red performance map is the visual signature of capacity-limited service.
Vodafone
Slowed but still serving.
EE
5G everywhere, throughput nowhere.
VMO2
Strong signal, soft service.
Three
Signal present. Service absent.
Four takeaways for event organisers and venues.
Coverage maps don’t predict event experience
Operator-published coverage maps and signal-strength readings showed three of four UK networks running 5G NSA across Royal Portrush. The actual throughput tests revealed that on those same networks, only Vodafone delivered usable data to a meaningful share of users. Pre-event coverage maps are necessary, not sufficient.
Network choice is decisive
At The Open, a spectator on Vodafone had a measurably different mobile experience from one on Three — not slightly better, an order of magnitude better. For venues, sponsors, ticketing partners and broadcast crews, the “which SIM are you on” question is the difference between functional and broken.
Temporary cell deployments don’t guarantee performance
All four operators were visibly present with temporary infrastructure at the venue (a tower visible behind the hospitality tents is in the hero image above). Three still failed almost completely. Presence of infrastructure is one thing; commissioned capacity that actually carries traffic is another.
Measure throughput, not just signal
If you want to know how a venue will perform, the signal-strength survey is the easy half of the job. The hard half — throughput tests, time-of-day sampling, per-operator capacity behaviour — is the half that predicts what actually happens when the crowd arrives. NetworkUX runs both at the same time, on the same routes.
Get the data before the crowd arrives.
NetworkUX provides before, during and after mobile performance monitoring for events of any scale — from a single venue to a town-wide festival to a championship-week takeover at a links course on the Antrim coast.