How to Check eSIM Compatibility: 3 Tests Before Sign-On

Updated 25 September 2026 · esim, phones, connectivity

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To check eSIM compatibility on an old or unlocked phone before you sign up for a plan, run three free tests at home. First, dial *#06# and look for an EID, a long identification number — usually 32 digits — that shows the phone contains built-in eSIM hardware, not just a slot for a physical SIM card. Second, check the phone's settings to confirm it carries no carrier lock. Third, enter the phone's IMEI, the device's own serial number and a different value from the EID, into the compatibility checker on the website of the exact carrier or eSIM provider you plan to buy from. Each test answers a different question: whether the hardware exists, whether it is unlocked, and whether one specific network will accept it. Passing one test does not mean the others will pass too, so skipping any of them risks paying for a plan the phone cannot use.

This guide explains what each of the three checks proves and where each one stops, what to do when the checks disagree, and what to confirm before paying for anything.

Why one eSIM compatibility check is never enough

A single check only answers one of three questions that decide whether an eSIM will work. The phone needs an eSIM chip inside it. It has to be free of a carrier lock. And the network you are buying from has to accept that exact phone model and regional version. The *#06# code answers the first question. The lock screen in settings answers the second. Only the carrier's own IMEI checker — the tool that looks the phone up by its serial number — answers the third.

Every source used for this article gives roughly the same three-step routine, and none of them offers one single test that replaces the target carrier's own check. That includes help pages from Airalo (an eSIM marketplace app), GigSky (an eSIM provider) and Roami (an eSIM app), plus a guide from eSIMRated, a site that reviews eSIM providers. All were read on 25 September 2026. A phone can have eSIM hardware and still fail on one network because of its model, its region, or a lock nobody told you about.

For travelers with limited access to a phone shop or reliable WiFi after departure — offshore crew who may not reach a port for three weeks are one example — a failed eSIM install is far harder to fix later than at home. Running all three checks before departure avoids paying for a plan the phone cannot use and losing an hour of scarce time ashore sorting it out afterward.

How to check eSIM compatibility in three steps

You can run all three checks in one evening at home, before you book anything or buy a plan. Do them on a working WiFi connection, and write down or screenshot every number the phone shows you, since you will need them again later.

Step 1: find the EID with *#06#

Open the phone's dialler app, type *#06#, and look at what appears on screen. If you see an EID — a long ID number, usually 32 digits — the phone contains an eSIM chip, not just a SIM tray. The help pages of Airalo, GigSky and Roami, all read on 25 September 2026, use this same check to confirm eSIM hardware.

If you see only one or two IMEI numbers (the phone's serial numbers) and no EID, treat the phone as having no eSIM until you get official confirmation otherwise. The same screen also shows the IMEI, which you will need for step three, so save it now. The EID check has one clear limit: it says nothing about carrier locks and nothing about any specific carrier. It only tells you the eSIM chip exists.

Step 2: confirm the phone is unlocked

An iPhone shows its lock status under Settings → General → About → Carrier Lock. According to eSIMRated's guide and GigSky's support page, both read on 25 September 2026, the words "No SIM restrictions" there mean the iPhone is unlocked.

Android is less consistent, since every phone maker puts this setting in a different place. GigSky's support page lists Settings → Connections → More Connection Settings → Network Lock Status for some Samsung phones. If your phone has no such menu, GigSky advises contacting the carrier directly. For an old phone bought years ago on a contract, the carrier is the only party that can confirm the lock was ever removed.

This step matters most for second-hand phones. A phone bought from a colleague or a market stall can look clean and still carry a lock from its first owner's contract.

Step 3: run the carrier's own IMEI check

Enter the phone's IMEI into the compatibility checker on the website of the carrier or eSIM provider you intend to buy from, and do this before you pay. T-Mobile's IMEI check page, read on 25 September 2026, tells users to get the IMEI by dialling *#06# or by checking phone settings. USA Mobile offers its own IMEI checker on its devices page, read the same day.

Use the checker belonging to the company you are actually buying from. A pass on T-Mobile's checker says nothing about USA Mobile, and a pass on USA Mobile's checker says nothing about T-Mobile. Each tool only reflects that one network's own rules.

What each eSIM compatibility check proves, and where it stops

The table below sums up what the research found for each tool. Every row is based on vendor pages or third-party guides, all read on 25 September 2026, so re-check before you rely on any of them.

The pattern is simple: checks near the top of the table are about your phone. Checks near the bottom are about someone else's system, the carrier's. You need at least one check from each half before you buy a plan.

Checking eSIM compatibility on an old phone: model and regional variant

On an old phone, check the exact model number and regional version, not just the product name. The product name alone is too vague. eSIMRated's guide, read on 25 September 2026, says Samsung's own IMEI lookup tool can identify the model and regional details. Google's support pages list Pixel eSIM compatibility by model and by carrier.

This is where second-hand and imported phones cause problems. Two phones with the same name on the box can be different hardware if they were sold in different countries. The model number under Settings → About is what you should search for. The name printed on the phone case is not specific enough.

Third-party databases can give a quick first look, but no more than that. Simology says its checker takes a model name or an IMEI and returns an "eSIM Capable" field. eSIMRated says the site IMEI.info returns the model, the manufacturing country, and the supported technologies. None of the sources shows these results are authoritative for a carrier's own activation system, and no one has published an accuracy figure for any of them.

When eSIM compatibility checks disagree before a contract

When your own checks pass but the carrier's checker says no, trust the carrier and do not buy the plan. When the carrier's checker says yes but something else looks wrong — a missing EID, or an unclear lock status — contact the carrier's support before you pay. The carrier's own system is what decides whether activation actually works.

Carrier checkers get things wrong too, and users have reported it happening. The research for this article found several user reports on Reddit. None of them has been independently verified:

1. Visible: a user reported that the compatibility checker marked devices as compatible while customer support said those devices were not set up for Visible's network. A separate report, dated November 2025, described the IMEI checker having problems specifically with eSIM support.
2. Tello: a user described a phone that supported eSIM in general but could not activate a Tello eSIM. The same post mentions someone using a different phone's IMEI to get around the block. Nothing in the sources shows that workaround is valid or allowed, so leave it alone.
3. Mint Mobile: a 2022 post said the checkout compatibility check was inaccurate and advised contacting Mint directly. That post is old enough that it tells you nothing about how Mint's checker performs today.

These reports show that a green checkmark at checkout does not guarantee the eSIM will activate. They do not show how often this happens — no failure rate has been published for any of these carriers. The practical rule: get a written answer from support any time two checks disagree. A chat transcript or an email is worth keeping, since it is what you would show support later if you ask for a refund.

Refunds: what to confirm before you install anything

The refund question has no single answer. It depends entirely on the carrier and the specific plan, and none of the sources used for this article publish a general refund policy that covers every case. That is exactly why you need to read the terms yourself before you pay.

Before you buy, look in the provider's terms for three things. First, check whether an unused, uninstalled eSIM can be refunded. Second, find out whether installing the eSIM profile counts as "using" it, even if you never actually connect. Third, see whether a failed activation is treated differently when the carrier's own checker had approved the phone. If you cannot find answers to all three, ask support in writing and keep the reply.

Pricing is one of the clearest ways to see how far a carrier's public information actually goes. T-Mobile publishes exact numbers: its U.S. Pass announcement, dated 7 May 2026, lists a 7-day pass at $25, a 10-day pass at $30, a 14-day pass at $35, and a 30-day pass at $50. The product page was last updated on 22 September 2026. According to that announcement, the 10-day pass includes 50 GB of premium U.S. 5G data and 20 GB of U.S. hotspot data, and every one of the four passes also includes unlimited talk and text within the United States. Those are the vendor's own figures as of September 2026, so re-check them before you buy.

USA Mobile, Visible, Tello and Mint Mobile are all named earlier in this article for their compatibility checkers, but none of the pages read for this piece publishes an equivalent, dated price list for those checkers' underlying plans. That gap is worth stating plainly rather than filling with a guess: if a carrier's pricing is not stated clearly on its own site, treat that as a reason to call support before you buy, not as a sign the plan is cheap or expensive. The point for this article is narrower anyway. A plan like T-Mobile's is tied to T-Mobile's own network rules, so T-Mobile's own checker is the one whose answer counts for that plan.

Buying and installing the eSIM before departure matters as much as running the checks, since a failure is far easier to resolve while you are still near a phone shop or reliable WiFi than after you have left. If installation has to happen later, with no WiFi on hand, plan for that separately before you go.

Honest pros and cons of checking it yourself

Doing these checks yourself costs nothing and catches the obvious failures early, before you have paid for a plan. It also has real limits.

What works in its favour:

1. It is free. The dialler code, the settings screens, and the carrier checkers all cost nothing to use.
2. It happens before you need the phone to work. You find a dead end while a phone shop is still nearby and you still have time to fix it.
3. It leaves a record. Screenshots of the EID, the IMEI, and the checker result are useful later if you need to talk to support.

Where it falls short:

1. Carrier checkers can be wrong. The user reports above show checkers approving phones that support later rejected.
2. Android lock status can be hard to find. On some models, the only way to confirm it is to call the original carrier, which is slow for an old phone.
3. Third-party databases have no published accuracy. A result from IMEI.info or Simology is a useful hint, not proof.
4. Passing every check is still not proof it will work. The only real test is activation itself, and that can only happen after you have paid.

Who should not rely on these checks alone

Some readers should treat a clean result as a maybe, and plan for the eSIM to fail anyway. If your phone came second-hand with no paperwork, or was bought in another country, the lock and regional-variant questions stay open until the carrier confirms them in writing. The same applies if your Android phone has no lock-status menu at all.

Anyone who depends on their phone for banking codes or two-factor authentication should keep a backup option too, in case losing access to their main number would lock them out of an account. A cheap, unlocked spare phone with a physical SIM slot is sensible insurance, whatever the checkers say.

FAQ

Does dialling *#06# prove my phone can use an eSIM?

It proves the phone has eSIM hardware if an EID appears, according to the help pages of Airalo, GigSky and Roami read in September 2026. It does not show whether the phone is unlocked or whether a particular carrier will accept it. Treat it as the first of three checks.

How do I know if an old Android phone is unlocked?

Look for a network lock setting in the phone's settings. GigSky lists Settings > Connections > More Connection Settings > Network Lock Status for some Samsung models. If your phone has no such menu, contact the carrier that originally sold it, which is what GigSky advises.

Can I trust a third-party eSIM checker like IMEI.info or Simology?

Use them for a quick first look and nothing more. They can report the model, origin and an "eSIM Capable" field, but no source shows they are authoritative for a carrier's activation system, and no accuracy figure has been published. The carrier's own checker always has the final say.

What if the carrier checker says yes but activation fails?

Contact the carrier's support with screenshots of the checker result, the EID and the IMEI. Users of Visible and Tello have reported this exact situation on Reddit, so it does happen. Whether you get a refund depends on that carrier's terms, which is why you should read them before buying.

Should I install the eSIM before I travel or wait until I arrive?

Install it before departure whenever the provider allows it, because a failure is easy to sort out at home and much harder once you have left. Check the plan's terms first, since some plans may start their validity the moment the profile is installed. If the terms are unclear, ask support in writing before you install.

Verdict

The three checks take one evening and cost nothing: EID first, lock status second, carrier IMEI checker last. Together they catch most dead ends before you pay. When the checks disagree, the carrier's answer decides, and a written reply from its support team is what protects your money. Do all of this before you pay, and keep the screenshots until the eSIM is actually live on the phone.

Related reading

1. Best eSIM for seafarers, ranked by cost