|Check network coverage:||SMARTY coverage||O2 coverage|
|2nd generation network. Max data speed of 0.3 Mb per second.|
|3rd generation network. Max data speed of 42 Mbps.|
|4th generation network. Max data speed of 1 Gbps (1000 Mb/s).|
|5th generation network. Max data speed of 10 or 20 Gb/s.|
|Use Wi-Fi for mobile phone calls and texts when no network signal.|
|4G Calling (VoLTE)||Yes||Yes|
|Voice over LTE (4G Calling) makes clearer HD calls over 4G networks.|
|Unused mobile data allowance rolled over from one month to the next.|
|Tethering allows you to share your mobile internet with other devices.|
|Network Frequency Bands|
|5G (NR) Frequency||3500 MHz||3500 MHz|
|4G (LTE) Frequency||800 / 1500 / 1800 / 2100 MHz||800 / 900 / 1800 / 2100 / 2300 MHz|
|3G (UMTS) Frequency||2100 MHz||900 / 2100 MHz|
|2G (GSM) Frequency||N/A MHz||900 MHz|
SMARTY is a UK mobile virtual network operator running on the Three network. SMARTY offers SIM-only plans with no lengthy contracts or credit checks, and provides monthly discounts on unused data from previous months.
O2 is a mobile network operator and telecommunications services provider in the United Kingdom, under the company name of Telefonica UK Limited. The company was originally formed in 1985 as Cellnet by the BT Group and was one of the earliest mobile phone networks to launch in the UK, and later rebranded as O2 UK.
02 is one of the largest network operators in the UK and provides 2G, 3G, 4G and 5G services to millions of customers in the United Kingdom, as well as to other mobile virtual network operators (MVNO).