Ten minutes, at home, on wifi

Set up your eSIM before you fly

Every eSIM problem we have ever seen traces back to doing this at the airport instead of the sofa. Do it the evening before.

Couple checking a phone together on a Greek ferry — Installed at home · online at the gate

Quick answerThe whole job: buy at home, install from the app or QR while on wifi, keep the new line off, fly, land, switch the line on with data roaming enabled for that line only. Validity starts at first connection, not at purchase, so installing early costs nothing. Checked August 31, 2026.

The four steps in order

Buy at home on wifi. Installation needs a connection, and airport wifi that demands a working phone number is a chicken-and-egg joke you don't want after a night flight.
Install, then switch the line off. App flow (Saily, GigSky, Airalo) or QR code. The eSIM appears as a second line; toggle it off so the clock doesn't start early.
On landing: line on, roaming on, for the eSIM only. Keep your home SIM active for SMS codes with its mobile data off, so it can't roam up a bill.
Give it five minutes, then go manual. No signal? Settings → network selection → pick Cosmote or Vodafone GR by hand (Saily supports both). A restart fixes most of the rest.

Your phone pick your side

iPhone

Path: Settings → Cellular → Add eSIM. Works on XS/XR and newer.

Check first: dial *#06#. An EID line on the readout means you are eSIM-ready. No EID, no eSIM.

Setup: label the new line "Greece", leave it off until landing. On arrival set it as the data line and keep your main line on for SMS codes with its data off.

Locked phone? Carrier-locked iPhones must be unlocked first; most US carriers unlock free once the device is paid off. Do this days before, not at the gate.

Android

Path: Settings → Connections (or Network & internet) → SIM manager → Add eSIM. Most Samsung, all Pixels, and recent mid-rangers qualify.

Check first: same trick, dial *#06# and look for an EID line, or search "eSIM" in Settings.

Setup: Greece line for data, home line for texts. Some dual-SIM Androids ask which line handles calls; pick your home line so nothing surprises you.

Samsung note: a few carrier-branded models ship with eSIM disabled even when the hardware has it. If SIM manager shows no Add eSIM option, that is why.

One rule for both: if the provider offers "install via app" versus "scan QR", take the app. It survives re-installs and phone swaps better than a one-time QR screenshot.

Troubleshooting symptom → fix

Symptom	Most likely cause	Fix, in order
No signal at all	roaming off on the eSIM line	Settings → the Greece line → data roaming ON → restart
Signal bars, no internet	wrong network attached or stale APN	pick Cosmote/Vodafone GR manually; toggle airplane mode; restart
"Unable to activate eSIM"	no wifi during install, or carrier-locked phone	redo install on wifi; check lock status with your carrier
Data burns absurdly fast	home SIM's data secretly active, or photo backup on cellular	home line data OFF; backup wifi-only; check per-app cellular list
SMS codes not arriving	home line fully disabled	re-enable home line for calls/SMS, keep only its data off
Hotspot won't start	plan or phone policy	fixed-GB plans allow it: toggle the data line, restart; on unlimited check the cap section of your plan

The night-before checklist ninety seconds

✓	Done at home, on wifi
1	eSIM bought and installed, line toggled OFF
2	Offline maps downloaded for every island on the route
3	Photo backup set to wifi-only
4	Autoplay off in Instagram/TikTok (saves ~30% data)
5	Home SIM: data roaming OFF, line itself ON for SMS codes
6	Provider app installed and logged in (top-ups, live data meter)

The classic three asked and answered

I landed and there's no signal.

Line on? Data roaming on for the eSIM line specifically? Then select the network manually (Cosmote or Vodafone GR) and restart the phone. This sequence resolves the vast majority of "it doesn't work" reports.

My eSIM activated while I was still at home.

Most plans start on first connection to a Greek network, so a home install should not start the clock. If your provider counts from install (rare), the app says so at checkout; that is the one case to install the night before, not the week before.

Data works but SMS codes don't arrive.

Codes go to your home number. Make sure your original SIM line is still enabled for calls/SMS, with only its data switched off. If you disabled the whole line, re-enable it; receiving texts abroad is free on most carriers.

Not bought yet? · 10GB · $21.99

Our overall pick installs in about two minutes from the app.

Get Saily for Greece

Sources & freshness: Flows verified against current provider apps, August 31, 2026. Which plan first: the main guide.