The telecom regulator measured the average download speed performance of retail 3G and 4G networks in cities such as Birmingham, Edinburgh, Glasgow, London, Manchester, Leeds, Newcastle and Poole/Bournemouth.
Ofcom said Vodafone is leading the average 3G download speed with 7.6 Mbps against O2 at 6.6 Mbps, Three at 5.4 Mbps and EE at 4 Mbps.
Ofcom said EE leads in 4G LTE upload speed with 17.6 Mbps against O2 with 13.2 Mbps, Vodafone with 13.1 Mbps and Three with 9.4 Mbps.
The telecom regulator said 3G operators such as O2, Three and Vodafone had 1.7 Mbps upload speed against 1.5 Mbps for EE.
In terms of latency for 4G LTE network, EE leads with 48.4 milliseconds against O2 at 55.2 milliseconds, Vodafone at 59.5 milliseconds and Three at 50.9 milliseconds.
On 3G network latency performance, Three leads with 53.3 milliseconds against EE at 54.8 milliseconds, O2 at 81.5 milliseconds and Vodafone with 73.3 milliseconds.
Ofcom used smartphones to measure four key metrics that relate to the experience of using a data connection: download speed, upload speed, web browsing speed (the time taken to load a web page) and latency (measured through ping tests).