TOP 10

COUNTRY : UK SUBSCRIBERS : 2.5MN NETWORK HOST : O 2

One of the UK ’ s most unique and widely used MVNOs , Giffgaff has been going for almost a decade with a no frills , low cost service . The company ’ s 30 day SIM-only plans offer some of the best value for money pay-as-you-go rates in the market , something Giffgaff achieves by having exactly no customer service , relying on its user community to raise and resolve issues .

COUNTRY : US NETWORK HOSTS : T-MOBILE , US CELLULAR

Frequently held up as the best MVNO for roaming customers , Google Fi uses networks operated by T-Mobile and US Cellular , as well as nearby wi-fi hotspots to boost network throughput . Although only US customers can use Google Fi , the service ’ s feefree tethering , and ability to switch between carriers abroad ( on some devices ) makes it a strong offering from an unexpected quarter . Late last year , Google-Fi also announced that it would start offering end-to-end encryption on its calls .