T-Mobile is turning a headache into migraine for some users by not fixing a recurring problem
Most carriers, including T-Mobile, let you use your smartphone's data to connect another device to the internet. This is called tethering or using a hotspot and many T-Mobile plans include mobile hotspot data. Some users have discovered that the hotspot data allotment gets used up even when they are not sharing their device's connection with another device.
Reddit user ViggoB12 has put out a PSA to inform T-Mobile users if they use VPN on cellular data, it will be counted towards hotspot data. Once the data cap is reached, throttling kicks in, resulting in slower speed.
This is a problem that first popped up around six years back and is not necessarily T-Mobile's doing. It's a bug that affects some Android phones with active eSIMs and certain VPNs, though at least one iPhone user also reported facing the issue.
VPN usage is sometimes mistaken for hotspot usage due to similar traffic pattern behaviour and the use of similar technologies such as encryption and Network Address Translation (NAT). T-Mobile allegedly previously said that "VPN services prevent the network from identifying and categorizing data usage which can cause the data to appear to be hotspot/tethering data." Of course, this response hardly adds any value as it doesn't offer any solution.
The good news is that most VPNs don't trigger this behaviour. If you have been experiencing hotspot throttling even though you don't use hotspot data all that much, it's possible that the VPN you are using is behind the issue. This could be frustrating since many people use VPNs as adblockers or for accession region-locked content.
If your VPN is triggering this issue, you might want to consider switching to another VPN. Also, since the problem seems specific to phones with eSIMs, getting a physical SIM is another workaround that has been suggested. If you are tech-savvy, you could try changing the maximum transmission unit (MTU) settings so that the value is as low as it is on cellular connections.
If you're using mobile data with a VPN, T-Mobile will count that toward your hotspot data and throttle you once it's all used up. They do not mention this anywhere in their Terms and Conditions. (I use express VPN).
ViggoB12, Reddit user, July 2024
My two cents here… I too have this issue, among many others but to throw a wrench in this thread I have an iPhone, not an android. I don't use a VPN. And, I have a physical SIM as opposed to an e-SIM. So, it's not just the Android users that experience it. As for the comment regarding the engineers should be embarrassed by this, I agree and would add a laundry list of other reasons why the entire company should be embarrassed beyond measure.
Cynically_Sane, T-Mobile user
I use a VPN to block ads. This is unacceptable to me, it should not be counted as hotspot data and I refuse to have advertisements shoved down my throat.
snaarb, T-Mobile user
One rep recommended to go back to physical sim AND WHAT DO U KNOW? PROBLEM SOLVED!
Legacy329, T-Mobile user
Although many T-Mobile customers have encountered this issue, T-Mobile has no official explanation for why it's happening and has not implemented a fix so far.
Things that are NOT allowed: