O2, Sky Mobile, and Three received the highest volume of customer complaints among pay-monthly mobile providers in the United Kingdom during the third quarter of 2025. New data from the communications regulator, Ofcom, reveals the operators facing the most significant customer service challenges, while the broader telecoms sector shows a year-on-year decline in complaint levels.
The figures, covering July to September 2025, measure complaints relative to each provider’s subscriber base. This methodology allows for a direct comparison, calculating the number of complaints per 100,000 customers. EE, Tesco Mobile, Vodafone UK, and iD Mobile generated the lowest relative complaint volumes in the mobile sector.
Complaint Drivers and Sector Trends
For the most complained-about mobile operators, the primary issues were distinct. O2 and Sky Mobile drew the most criticism for their handling of complaints themselves. Three’s customers reported the highest level of grievances related to faults, service problems, and provisioning issues.
Overall, the total number of complaints across all major telecoms services, including fixed broadband, landline, and pay TV, remained largely unchanged from the previous quarter. However, a comparison with the same period in 2024 indicates a broader downward trend in complaint volumes industry wide.
The breakdown underscores persistent pressure points for UK telecom companies, focusing on customer service quality, technical reliability, and the efficiency of resolving problems. The results highlight that networks are increasingly evaluated on their support experience alongside traditional metrics like network coverage and pricing.
Performance Across Other Services
The Ofcom data also detailed complaint levels for other telecommunications services. In the fixed broadband sector, EE, TalkTalk, and Vodafone attracted the most complaints from subscribers. Plusnet was noted for having the fewest broadband-related complaints.
For landline telephone services, TalkTalk also topped the complaints table. Utility Warehouse received the fewest complaints in this category. In the pay television market, EE was the most complained-about provider, while Sky and TalkTalk generated the fewest complaints.
Industry analysis indicates that the majority of complaints across all services continue to stem from service faults. This is followed by issues with how complaints are handled and disputes over billing. For consumers dissatisfied with their current provider, switching remains a viable option. Market data suggests millions of broadband customers are outside their minimum contract period and could potentially reduce their bills by seeking a new deal.
Regulatory Context and Next Steps
Ofcom publishes these quarterly complaints data to promote transparency and inform consumer choice. The regulator requires providers to make the data easily accessible to both existing and potential customers. The publication is part of ongoing efforts to drive improvements in customer service standards across the UK’s telecommunications industry.
Providers named in the report are expected to address the specific issues raised by the data. Historically, such publications have prompted internal reviews and public commitments from companies to enhance their customer service operations. Ofcom will continue its monitoring and publish the next set of quarterly figures, covering the final quarter of 2025, in early 2026, providing further insight into whether the identified trends and operator performances persist or change.
Source: Ofcom
