Where the data goes
When you browse over mobile data with a VPN connected, the phone sends traffic through the mobile network to the VPN service. The VPN changes the route and protects the tunnel, but it still needs the underlying mobile connection.
Encryption and connection management add overhead. The amount depends on how the service and connection operate, so a precise percentage without measurement would be misleading. If the mobile allowance runs out, turning on a VPN will not replenish it.
Look at activities before blaming the VPN
A long video call, a cloud-photo upload or a laptop update can matter more to your travel budget than the background connection. Look at the timing of a usage jump and which apps were active before making changes.
Also check whether the phone moved from Wi-Fi to mobile data when the Wi-Fi connection weakened. A download you expected to finish over hotel Wi-Fi may be using the eSIM instead. Your selected SIM and data-switching settings are worth reviewing.
Why a VPN can change connection speed
The route to a VPN server adds another part to the journey. Server distance, network congestion and the underlying mobile signal can affect responsiveness. A VPN cannot guarantee a faster connection, nor does a 5G label guarantee a particular speed.
If a connection feels slow, compare simple tasks rather than repeatedly running large speed tests that consume the allowance. Check signal, try another location and review the VPN connection. For a work device, follow your employer’s network policy before changing its VPN setup.
Budget for the way you actually travel
Choose a data plan using a realistic estimate of your daily use and a buffer. Move large, predictable downloads to before departure. During the trip, compare remaining data with the number of days left in the Stellar eSIM app.
Keep the distinction clear: the eSIM has a data allowance and validity; the included Stellar VPN has an access period linked to the plan. Free VPN access does not mean unlimited cellular data. If you buy a top-up, read its conditions rather than assuming every part of the original bundle is extended.
Sources & further reading
Product information and device guidance used for this article. Check your selected plan and exact device before purchase or setup.
