
25/06/2025
Three UK Faces Major Voice and SMS Network Outage Across UK
On June 25, 2025, Three UK suffered a widespread outage affecting voice calls, SMS, and voicemail services, while mobile data remained functional.
The disruption began around 8am, impacting users across Three UK and its virtual operators like iD Mobile and Smarty. Customers experienced silent call failures and inaccessible voicemail, with 27% of users affected.
Engineers identified network component congestion as the likely cause, implementing rerouting strategies to ease traffic. However, call setup degradation reached 84.48%, with a 75.8% overall service impact. Although data services functioned, SMS issues persisted, and emergency service access was still being evaluated.
By 5pm, some improvements were reported, though about 20% of 4G users still lacked SMS service. Users were advised not to restart phones to avoid losing connectivity. Three UK apologized and continued working to resolve the issue, which remains one of the company’s most disruptive outages to date.