The regulator looked at data from EE, O2, Three, and Vodafone on the performance of their networks.
EE had the best service across the whole of the UK, with O2 leading in cities.
Ofcom said that research showed the consumers in urban areas were happier with their mobile phone service than those in rural areas.
Some 78% of people in urban areas were satisfied with their mobile network, compared with 67% in rural parts of the UK and 70% in remote areas, Ofcom said.
The research measured the quality of calls in areas with coverage, looking at the numbers that failed to connect or unexpectedly cut out.Six months of data
Ofcom used data from RootMetrics, a company that measures network performance on mobile handsets, which showed the proportion of UK mobile phone calls connected successfully during the second half of 2013.
It said that overall:97% of all calls on the EE network were successfully connected 95.3% on O2, 94.5% on Three, and 92.6% on Vodafone. Continue reading the main story “Start Quote
We should all be able to get mobile reception, whether we're in the heart of the city or out in the sticks”End Quote Ernest Doku uSwitch
In terms of rural calls:93.7% on the EE network were successfully completed 87.4% on O2, 86% on Three, and only 79.9% on Vodafone.
"Regular independent testing of our network shows that we're the market leader for call set-up," Vodafone said. It also said that it recently launched a scheme called Rural Open Sure Signal to "extend coverage in hard-to-reach rural locations".
Ofcom said that all four networks have agreed to work with it to develop a common methodology for measuring the rates of successful mobile phone calls.Dropped calls hit 20%
EE said: "It's great to see our ongoing investment in phone calls reflected in Ofcom's report, confirming that we continue to provide the best call experience across the UK, particularly in rural areas.
"We're investing hundreds of millions each year in expanding the reach of our network so that more people can make phone calls in more places," it added.
Three said that the data looks at "one measure of network performance but YouGov's surveys of iPhone, smartphone, tablet and mobile broadband users consistently suggest our customers are the most satisfied across a number of measures".
And O2 said: ""We are pleased to see that we are the best network in urban areas across England and the UK, where the majority of our customers are."
Ofcom also said that the majority of people it surveyed never or hardly ever had a blocked call or dropped calls. "However, a fifth of people said they experienced blocked calls and dropped calls at least once a week, and this increases in rural areas," it said.
"While it's good to see that the majority living in cities are satisfied with their networks, this doesn't help me if I'm in a field, in rural Wales, with a broken leg and unable to call for help."