How to activate an eSIM
Installing and activating an eSIM are two different steps. After installation the profile simply sits on the phone; it activates the moment it registers on a network in a country your package covers. On arrival, turn your Mongolian line off, switch the GlobalSIM line on and enable Data Roaming for that line so it can attach to the local network.
How long does activation take?
Usually under a minute from the moment the eSIM finds the local network. If the phone stays without service, toggle Airplane mode on and off once, or select the network manually.
Why is Data Roaming needed at all?
Because a travel eSIM always uses a partner network abroad — that is roaming by definition. Data Roaming is the switch that allows the line to use that network, and the data comes out of the package you already bought.
What should I do right after landing?
Turn the Mongolian line off, turn the eSIM line on, set Mobile Data to the eSIM and switch Data Roaming on. With the home line off, nothing is ever billed to your Mongolian number while you travel.