Your Micro-Sim on Three - Pre-loaded with 3GB and valid up to 30 days Get a 3G Micro-SIM from Three and connect your device to the UK’s biggest 3G network. We’ve got the best value data plans on the market and no other network gives you more data for your money. Please note that our 3G Micro-SIM will only work in a compatbile device. Pay As You Go •Your Micro-SIM is already loaded with the data allowance you've chosen •1GB data allowance •Valid for 30 days •Top-ups available: 1GB £10 3GB £15 7GB £25 When you run out of data you can buy a top-up plus an Add-on, if required.