Travel eSIMs may need Data Roaming enabled to use the local networks included in the plan. Follow the instructions for your exact SimFuse eSIM.
iPhone
Open Settings > Cellular or Mobile Data, select the SimFuse line and enable Data Roaming. Depending on iOS and the number of lines, the setting may be inside Cellular Data Options.
Android
On Pixel, open Settings > Network & internet > SIMs, choose the SimFuse line and enable Roaming. On Samsung, check Connections > Mobile networks and SIM manager. Names and whether roaming is controlled per line vary by model.
If a roaming switch is not clearly tied to one SIM, first confirm which SIM handles mobile data. Do not enable roaming blindly on both lines.
Test the travel line
Select SimFuse for mobile data, then test a small webpage with Wi-Fi off. Check that you are in the plan's coverage and that it has data and validity left.
Leave home-SIM roaming off unless you want it and know the cost. Data-roaming settings do not control every possible charge for calls and texts.