The changes were announced last year and were made following the UK’s exit from the European Union.
Three is also planning to introduce charges to its customers from May, while O2 said it will allow its customers' free roaming in the EU.
Ernest Doku, mobiles expert at Uswitch.com has urged mobile users to check if they will be affected by the changes.
“UK customers travelling to the EU will have to pay £2 a day for access to data and minutes they have already paid for,” he said.
Charges depend on when customers last upgraded their contracts. For EE customers, the charges apply to customers who joined or upgraded after July 7, 2021.
For Vodafone and EE customers, the charges apply to those who signed contracts on August 11 2021 and October 1, 2021 respectively.
“If you’re going on holiday or travelling abroad for a longer time, you can save money by paying for multi-day passes with Vodafone, or Roam Abroad with EE,” Doku added.
“If you’re an existing customer of EE, Vodafone or Three, check your contract to see whether these charges apply to you. If you signed up prior to specific dates, you should be safe.
“When it comes to travelling, don’t leave it until the last minute to check the roaming charges for your destination, and use hotel and cafe Wifi when on holiday where possible, ensuring any public access points are safe and secure before logging on.”
PP Foresight analyst Paolo Pescatore says the reintroduction of roaming charges demonstrate the "harsh realities" of Brexit are becoming more evident in the telecoms world.
Although he maintains that introducing roaming charges is an easy commercial decision to help UK telcos to improve margins.
"All telcos are struggling with margins being squeezed and are seeking ways of increasing revenue while investing billions in costly next generation fixed and mobile networks.
"A saving grace for phone users is that the telcos have made moves designed to avoid unexpected bill shocks."
Pescatore adds that phone users will need to be savvier when travelling abroad and customers will be forced to switching to Wi-Fi or looking at local e-SIM options.
With O2 yet to reintroduce roaming charges, "all eyes" are on the operator on whether it will make the same move as its competitors.
"For now, it will seek to maintain its existing position for as long as possible to ensure some form of differentiation over rivals, however, it will have some time given the current challenges and uncertainty due to the pandemic."
