Just back from Overseas and used Covermore Global Sim...very difficult to make work. I inserted into my iphone7 plus which has Telstra Account. Coming back to Australia...could not get Data. Put my Telstra Sim in my wife phone...data worked...pot my wifes Optus SIM in my Telstra phone and it worked. Telstra Shop no real help, ot online Telstra no real help. Apple guy on line got me to Factory Reset iphone wholst downloading all mt stuff to itunes. Did that and data worked on factory reset. However when I restored with my stuff....data did not worl. So factory Reset again and added Apps separatly. Now all good. My understanding is some Policy of an overseas Telco has got on the Iphone and Telstra cannot override. However it seems ok with Optus. My recommendation is do not touch Covermore Global Sim...and just use Telstra $10.00 a day roaming.