The increase will kick in from 1 November and will mean that customers travelling on our trains will be able to stay connected at faster speeds for longer.
This investment goes hand in hand with Transport for Wales' commitment to invest £40 million in refurbishing our current fleet of trains and installing plug sockets and USB charging points.
With more services running than ever before on the Wales and Borders and Core Valley Line networks, the importance of keeping people connected has grown. The move will mean customers can send more emails, check social media, keep up-to-date with the latest news and check onward journey details in real time.
Customer Experience Director for Transport for Wales Colin Lea said: "We know technology is never static so we have to keep looking at what we give our customers and seeking to improve wherever we can.
"Increasingly people need to be online whilst on the move and this will give our customers the confidence to know they can work or browse on our services for longer.
"We're in the process of putting three pin plug and USB sockets on trains too so our customers should no longer need to keep an eye on their batteries."
Once your free data runs out you can still keep connected at limited speed throughout your journey.
Free WiFi was first introduced on the Wales and Borders network at the start of 2018 thanks to a £1.5 million Welsh Government investment in the fleet. And since then there has been a significant upturn in usage with customers taking advantage of the offer.
(The interior of a newly refurbished Class 153 train, which has had plug and USB sockets installed)