Little will change. However, from June, O2 customers moving to Three will be able to take advantage of Three’s 4G service. O2 stores are now 3Stores; O2 customers registered for Priority Tickets will be able to get presale tickets for the 3Arena; and customers should visit three.ie for their account details and payments.There have been no changes to your contracts, though you will now be able to make free calls to Three mobiles if free O2 to O2 calls had been part of your plan. You won’t need to get a new SIM and your mobile number stays the same.For more information related to the switchover, visit the dedicated webpage on Three’s website.Three acquired O2 last summer for a reported €780 million. EU regulators gave the green light under the condition that Three would assist two new mobile operators to set up. As a result, Carphone Warehouse and UPC will launch their own mobile networks later this year.Three's takeover of O2 Ireland is entering its final stages with former O2 customers now under the Three umbrella. Read on for the minor changes.