29 Aug 2025

TrawsCymru T4 bus service is set for an upgrade, with Transport for Wales (TfW) announcing a new timetable to deliver improved frequency and reliability.

The upgraded service, operated by mid Wales-based Celtic Travel, will launch on Monday, 1 September 2025, continuing to connect communities between Newtown and Merthyr Tydfil.

The T4 route has been a vital link for commuters, students, residents, and visitors for over 14 years, serving destinations including Bannau Brycheiniog, the Royal Welsh Agricultural Show, and many picturesque towns and villages along the way. 

What’s new from 1 September? 

• Operating every 2 hours between Newtown and Brecon, Monday to Saturday  
• Hourly service between Brecon and Merthyr, Monday to Saturday  

• Sunday service every 2 hours, with hourly summer peak enhancements between Brecon and Merthyr  

• A new cost-effective fares structure, aligned with the wider TrawsCymru network  

• New vehicles arriving in March 2026, offering improved comfort and environmental performance 

The service will be delivered in partnership with Williams Coaches of Brecon, ensuring local expertise and dependable operations. 

Lee Robinson, Executive Director for Regional Transport and Integration at Transport for Wales, said: “We’re excited to launch the enhanced T4 service with Celtic Travel. These improvements will offer greater flexibility and value for passengers, and the partnership model shows how regional operators can successfully collaborate to deliver high-quality public transport.” 

Phyl Davies, Managing Director at Celtic Travel, added: “We’re proud to be taking on the T4 service and look forward to working closely with Transport for Wales to deliver a high-quality, dependable service. The new timetable and fare structure will offer greater flexibility and value for passengers, and we’re excited about the arrival of new vehicles next year to further enhance the journey experience.” 

Cardiff–Merthyr Changes 

From September, Stagecoach will launch a new X4 service between Merthyr and Cardiff, running every 60 minutes, Monday to Saturday, and serving Treforest Industrial Estate to improve access to employment, education, and leisure.

Rail alternatives remain available, and Transport for Wales is exploring integrated ticketing options to support seamless travel.