It is a short call and it always sounds the same: they have landed, the phone says no service or no data, and you are the person whose number they have. Whatever caused it, you now own it.
In practice it is almost always one of five things. Three can be fixed from the terminal, two cannot — which is exactly why the prevention matters more than the troubleshooting.
1. The eSIM was never installed
By far the most common. The QR code arrived, the traveller meant to deal with it later, and later turned out to be a terminal with no Wi-Fi.
From the airport: fixable. Airport Wi-Fi is enough to install. Have the confirmation email to hand.
Prevention: tell them to install before leaving home, and tell them why — installing does not start the plan on most packages, so there is no cost to doing it early.
2. The line is installed but switched off
The eSIM is there, sitting as a second line, with data still pointed at the home SIM — which is roaming, expensive, and often disabled.
From the airport: fixable in about thirty seconds, in the phone’s mobile data settings. Select the travel line for data, leave the home SIM on for calls.
Prevention: one screenshot in the pre-departure note. This single image removes more arrival calls than any amount of written instruction.
3. The phone is carrier-locked
The handset is eSIM-capable but the operator has locked it, so it refuses a second profile.
From the airport: not fixable. The unlock has to come from their own carrier and takes days.
Prevention: this is the one that has to be checked at booking. Ask whether the phone is unlocked and point at the compatibility list.
4. They expected calls and texts
Not a fault at all, but it generates the same call. A travel eSIM carries data. Their own number is still on the physical SIM — WhatsApp, iMessage and every other app work normally over the data plan.
Prevention: say it plainly in advance. “Your number stays yours for calls and texts; this is the data.”
5. Wrong plan for the route
A plan bought for one country, on an itinerary that crosses into another. It works perfectly, in the wrong place.
From the airport: fixable, by buying the right plan then and there — but it is an avoidable second purchase.
Prevention: for any multi-country itinerary, recommend a regional plan from the start.
Four of these five disappear with one paragraph in the pre-departure email: install at home on Wi-Fi, check the phone is unlocked, select the travel line for data on landing, and keep your own SIM on for calls. It is worth templating once.
The note worth sending
Something close to this, two weeks out and again at 48 hours:
Your mobile data for the trip is attached as a QR code. Please install it before you fly, while you are on Wi-Fi — it will not start using data until you land, so there is no cost to setting it up early. Your phone needs to be eSIM-capable and not locked to a carrier. When you land, go to mobile data settings and choose the travel line for data; leave your usual SIM switched on so you keep your number for calls and texts.
Stop taking the arrival-day call.
Whether you resell data or simply recommend it, getting travellers set up before departure is the whole game. We can help you package it.