A record 222,036 customers switched to small and mid-tier suppliers in June, the highest number ever recorded by Energy UK.
In total 481,677 customers switched during the month, with a net 46 per cent of these switching from larger providers to smaller providers.
Compared to June 2017, last month saw 19 per cent more customers switch supplier.
A breakdown of the figures shows 53 per cent went from larger to small and mid-tier suppliers while seven per cent went from small and mid-tier to larger suppliers.
So far in 2018 more than 2.7 million customers have switched supplier.
Ofgem said it is working to make the market “more competitive”.
An Ofgem spokesperson said: “Switching is the best way for consumers to save money, so it’s great more people are doing this, but there are still too many consumers who are paying too much for their energy.
“This is why we are putting price protection in place to protect those people who don’t switch whilst we work with suppliers to make the market more competitive and better for consumers.”
Confidence in switching is also increasing, with nine in 10 customers saying they are happy with the process according to the latest research from Energy Switch Guarantee.
Lawrence Slade, chief executive of Energy UK, said: “The record numbers switching to small and mid-tier suppliers show that more and more customers are taking advantage of the ever-growing competition and choice out there.
“It only takes a few minutes to either check with your own supplier or to look at what’s on offer from nearly 70 competing suppliers in the market.
“With the Energy Switch Guarantee in place consumers should feel even more confident that switching will be simple, speedy and safe.”