Yes, to use any travel eSIM, including those for London, your mobile phone must be unlocked by your home carrier. An unlocked device allows you to install and activate an eSIM profile from a different provider like Cellesim, ensuring you can access 4G or 5G data across the UK's networks.
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Does my phone need to be unlocked to use an eSIM in London?
Updated May 30, 2026
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