ST+ Mobile can be configured to search for and use the strongest signal mobile phone network, regardless of preferrence for a particular mobile operator network (if this is of interest to you, please let us know) but by default will route via the UK's O2 mobile operator network.

Therefore, upon first time used of your ST+ Mobile SIM you may be required to choose a network and/or select from a series of listed mobile operator network options: select 'O2 Pre Pay'.