Why roaming can be required
A travel eSIM may be issued by a provider whose home network is not in the country you are visiting. It connects to a supported local carrier through a roaming agreement, so the phone can require Data Roaming to be enabled for that eSIM profile.
The important distinction
Enabling roaming on the travel eSIM is different from enabling roaming on your normal home SIM. The safest setup is to choose the travel eSIM as the mobile-data line, enable roaming only where the travel plan requires it, and keep data roaming disabled on the home line unless you intentionally want to use your carrier roaming plan.
What to check after landing
Confirm the travel eSIM is turned on, selected for mobile data and allowed to roam if the plan requires it. If data still does not work, check network selection and APN instructions from the plan.
Avoid accidental home-SIM data
On dual-SIM phones, features such as cellular-data switching can move data back to another line. If you want strict control, disable automatic cellular-data switching while traveling.
Use the travel eSIM for mobile data. Keep roaming off on your normal SIM unless you know exactly what your home carrier charges.