New independent testing has revealed a clear hierarchy in the performance of the UK's major mobile networks, with Three Mobile surging ahead to claim the title of the country's fastest provider.
The Speed Test Results: A Clear Winner Emerges
According to comprehensive data from global analyst Ookla, covering the third and fourth quarters of 2025, Three delivered a decisive victory in overall speed performance. The network achieved a top Speed Score of 53.46, which combines download and upload speeds with latency.
Most strikingly, Three's median download speed reached an impressive 214 megabits per second (Mbps). This figure is more than 80Mbps faster than its closest competitor and is, notably, twice as fast as the UK's average fixed-line broadband speed.
Vodafone secured second place with a Speed Score of 43.05 and a median download speed of 129.78Mbps. EE followed in third with a score of 36.73 and downloads of 97Mbps. O2 finished at the bottom of the table across all measured categories, recording a Speed Score of 30.70 and a median download speed of 78.92Mbps.
Understanding the Data and Its Caveats
Ookla confirmed the findings, stating: “3 is the Fastest 5G Network in the United Kingdom, Q3–Q4 2025. The Speedtest Award for Fastest Network is based on Speed Score and provides a measure of a network’s throughput and responsiveness.”
However, experts caution that mobile network performance is inherently variable. As noted by industry publication ISPreview, real-world speeds are influenced by numerous factors including a user's location, whether they are indoors or outdoors, network congestion at different times of day, and constant movement. Therefore, while the Ookla data provides a robust national overview, individual experiences may differ.
The Future: Impact of the Vodafone-Three Merger
The performance landscape could be set for further significant change following the major merger between Three and Vodafone, which was finalised in May 2025. The combined entity, VodafoneThree, has pledged an £11 billion investment to construct what it aims to be the UK's premier mobile network.
The integration process is already underway, utilising Multi-Operator Core Network (MOCN) technology. This system allows customers of both Vodafone and Three to automatically connect to whichever of the two networks offers the strongest signal at any given time, at no extra cost. The long-term goal is to deliver substantially wider geographic coverage and more consistent performance for subscribers nationwide.
For consumers, these latest rankings offer a valuable snapshot of current network capabilities, while the ongoing merger signals a period of potential improvement and intensified competition in the UK's mobile market.
