Galaxy S21 eSIM: a clean yes, and how to set it up properly

A yes without footnotes

The Galaxy S21 supports eSIM. Our data carries no regional note against it, no variant exception and no asterisk, which makes it one of the plainer entries in the whole list — eSIM plus a physical SIM tray, as far as we have recorded, wherever it was sold.

That means there is not much to argue about, so this page spends its length on the thing that actually decides whether the eSIM saves you anything: how you set the phone up.

The setting that decides your bill

Two active lines means two lines capable of costing you money. The travel eSIM is prepaid and cannot surprise you. The home SIM can, because by default it is free to roam.

Before you fly:

The last row is the one people skip. Turning data roaming off for the home line specifically — not the line itself, just its roaming — leaves you reachable on your usual number while making it impossible for the phone to quietly fall back to your carrier's roaming rates when the eSIM's signal dips.

What your home carrier charges for incoming calls and texts while abroad is between you and their roaming terms, and it varies enormously by country and plan. We are not going to guess at it. Data is the part that runs up a bill with nobody touching the phone, and that is the part this closes off.

Why keep the home line at all

Because the number is where everything already points. Banks send verification codes to it, airlines send delay notifications to it, and the person collecting you from the airport has it saved. An eSIM gives you a new number that nobody knows and no service is expecting.

Running both is the point of dual SIM. Data on the cheap line, identity on the familiar one.

It also removes the main reason people give up on travel eSIMs after one attempt. Used as a replacement for the home SIM, an eSIM is a slightly awkward product: you get cheap data and a number nobody can reach you on. Used alongside the home SIM, which is what an S21 lets you do, it is just cheaper data with no other consequence at all.

Install before you fly

Installation needs an internet connection, which is precisely what you will not have standing at baggage reclaim. Buy the plan at home, scan the QR code over wifi, and let the profile download while you still have a working connection. Most plans do not start counting until the profile connects to a network abroad, though that is set by the provider — check the terms if the trip is a week away rather than tomorrow.

If it refuses to install

Three things account for most failures, in order of likelihood:

• A carrier lock. A handset sold on contract may reject third-party profiles. Carriers unlock on request once the device is paid off.
• A QR code that has already been used. Codes are typically tied to one installation. If you scanned it on another phone, it is spent.
• Manual details typed wrong. If you are entering activation details by hand rather than scanning, one wrong character fails silently.

None of those is a hardware problem. On an S21, the hardware is not the question — dial *#06# and the EID will be sitting there next to the IMEI.

The compatibility checker covers the rest of the range, our comparison covers the plans, and how we test explains where our numbers come from.