There are three options when purchasing a mobile Wi-Fi router: Buy a device and data SIM bundle direct from a mobile operator in return for a fixed monthly subscription Buy a network-unlocked MiFi router and add your own data SIM Hire a mobile router to cover only the period you need (see MyWebspot, reviewed above) Many people will automatically go to their mobile operator for a MiFi device, since it's an easy solution and you don't need to pay anything up front. But this isn't always the best idea. If you buy a MiFi router from a mobile operator it will probably be locked to that network, preventing you from shopping around for the best data deal. You will also most likely pay over the odds if you choose to pay nothing up front but tie yourself into a two-year contract. However, buy a network-unlocked router and shop around for a great-value data SIM plan and you will save money in the long run. Note that the mobile hotspots offered by UK mobile operators are typically made by Huawei, but also Netgear, HTC and TP-Link. If you know the model you can usually find these devices available network-unlocked through retailers such as Amazon.