3G and 4G mobile broadband coverage is good in large population centres, but limited or nonexistent in rural areas.
Since 2016, EU citizens have been able to use their home data allowances across the EU zone (including the UK, at least for now), but data roaming charges can be very high for other overseas travellers – check with your mobile/cell phone provider before travelling.
Most hotels, B&Bs, hostels, stations and coffee shops (even some trains and buses) have wi-fi access, charging anything from nothing to £6 per hour.
Thanks to the prevalence of 3G and public wi-fi zones, internet cafes are becoming increasingly rare in England, especially away from big cities and tourist spots.
Public libraries often have computers with free internet access, but only for 30-minute slots, and demand is high. All the usual warnings apply about keystroke-capturing software and other security risks.