Identity: four numbers and an eUICC ID
Subscription, card, device, number and chip: which identifier answers which question, and what a SIM swap actually changes.
An IMSI names the subscription, an ICCID names the card or profile container, an IMEI names the device, and an MSISDN is the diallable number. An eUICC adds the EID, which names the chip, and the LPA, which downloads profiles. Each answers a different question, and each changes for a different reason.
Key facts
- An IMSI is at most 15 digits: a 3-digit MCC, a 2- or 3-digit MNC, then the subscriber identity.
- An ICCID is at most 20 digits and starts with 89; it identifies the card or the profile container.
- An IMEI is 15 digits: an 8-digit TAC, a 6-digit serial and a Luhn check digit. A SIM swap does not change it.
- An eUICC EID is 32 digits and stays with the chip when profiles are downloaded or deleted.
- Portability moves the diallable number; the IMSI stays with the subscription.
After this module you can
- Choose the identifier that answers a subscription, card, device or number question.
- Explain what changes on a SIM swap and what does not.
- Read the structure of an IMSI, ICCID, IMEI and EID from the left.
On this page
Start with the question, not the number
An identifier is only useful when it answers the question in front of you. A support ticket that says the device is blocked needs the IMEI. A subscription that will not authenticate needs the IMSI. A card that was replaced needs the ICCID. A number that does not ring needs the MSISDN. Ask the question first, then choose the identifier.
Each identifier has an owner and a place to live. The IMSI lives on the SIM or eUICC and in the subscriber database. The ICCID lives on the card and in the inventory; for an eUICC it names the profile, not the chip. The IMEI lives in the device baseband and on the label. The MSISDN lives in the subscription record. The EID lives in the eUICC hardware.
The names look alike in a spreadsheet and behave differently in a swap. Keep them in separate fields with their own validation, and keep a history instead of overwriting the old value. A clean data model has one row per subscription, one per card or profile, and one per device, joined by explicit identifiers.
One value, split into fields
Decoded in your browser. Nothing is uploaded.
- Industry identifier
- 89
- Issuer and account
- 9900000000000000
- Check digit
- 5
- Check
- Valid
Text description
The ICCID starts with 89, the major industry identifier for telecommunications. The parser then separates the issuer and account part and the check digit, and verifies the check. The same panel accepts a pasted value and never sends it anywhere. IMSI, IMEI and EID have their own splits: MCC, MNC and MSIN for the IMSI; TAC, serial and check digit for the IMEI; and a 32-digit structure for the EID.
What a SIM swap changes
A SIM swap changes the card and usually the subscription identity. The new card has a new ICCID. The subscription may keep its IMSI or move to a new one, depending on how the operator provisions the replacement. The IMEI does not change, because the device did not change. That is why a blocked device stays blocked after a SIM swap.
The diallable number is separate again. Portability moves the MSISDN to another network, while the IMSI stays with the subscription that serves it. A number can also be recycled and reassigned. Never use the MSISDN as a permanent customer key.
An eSIM swap changes the profile, so the ICCID changes and the IMSI may change. The EID stays with the chip. An inventory that keys only on ICCID cannot answer which chip holds a profile; add the EID to the join.
Who asks for which
| Item | Question | Identifier | Who asks | Changes on a SIM swap |
|---|---|---|---|---|
| Who is the subscriber? | IMSI | Provisioning and the core | Usually: the new card is provisioned with a subscription identity | |
| Which card or profile? | ICCID | Logistics and activation | Yes: the new card or profile has a new ICCID | |
| Which device? | IMEI | Device inventory and registration | No: the device is the same | |
| Which number does the user dial? | MSISDN | Billing, support and the customer | Not by the swap; portability moves it separately | |
| Which chip holds the profiles? | EID | eSIM provisioning and inventory | No: the chip is the same |
A device block follows the IMEI. A subscription block follows the IMSI. They are different controls.
Read the digits from the left
Read an IMSI from the left: a 3-digit MCC, a 2- or 3-digit MNC, then the MSIN. The total is at most 15 digits. The MNC length is set by the registry, so do not count a fixed number of characters. Use the MCC-MNC table for the network, not the shape of the string.
An ICCID starts with 89, the major industry identifier for telecommunications, then an issuer identifier and an account number. The full string is at most 20 digits. An IMEI is 15 digits: an 8-digit TAC, a 6-digit serial and a Luhn check digit. An IMEISV replaces the check digit with a 2-digit software version, for 16 digits.
An EID is 32 digits. It starts with an industry identifier, then a country code, an issuer identifier and an individual number, and ends with check digits. The EID names the secure element; the ICCID names the profile. The LPA is not an identifier: it is the software component that talks to the provisioning servers and enables or deletes a profile.
The eSIM pair: EID and LPA
| Term | What it names or does | Changes when a profile is downloaded? |
|---|---|---|
| EID | The eUICC chip | No |
| LPA | The device software that downloads and manages profiles | No; it acts on the profile |
| ICCID | The card or the profile container | Yes; the new profile has its own ICCID |
| IMSI | The subscription the network authenticates | Usually; the new profile brings its subscription identity |
Documentation-safe values only. The sample ICCID is not a live card.
What the ticket carries
Collect the identifier that matches the failure, then add the rest for context. A registration failure needs the IMSI, the device's supported bands and the network it last saw. An activation failure needs the ICCID and, for eSIM, the EID. A blocked device needs the IMEI. A delivery failure needs the MSISDN and the receipt code.
Add the APN, the module model, the firmware version, the timestamp in UTC and the last known cell or network. The formats are fixed, so a format check removes the most common false alarm before the ticket opens. The identifier toolkit checks the structure and the check digits in the browser.
The MCC-MNC lookup names the network that owns a PLMN; it is not a blame tool. The phone validator checks a number's structure, not whether it is reachable. For the profile side, read what an eSIM is and what multi-IMSI does.
A SIM swap is not a device swap
Myth
Myth: a new SIM means a new device identity.
Fact
Fact: the SIM carries the subscription and the card identity. The IMEI stays with the device. A device block follows the IMEI, not the card.
Check your understanding
-
A customer swaps a SIM and the device is still blocked. Which ID did not change?
The IMEI. The card and usually the subscription identity changed; the device did not. Check the device block against the IMEI, then check whether the new subscription is allowed on the network.
-
Which ID answers which card is in the box?
The ICCID. It is printed on the card and scanned in logistics. The IMSI belongs to the subscription, not to the box.
-
Which ID can move to another operator?
The MSISDN, under portability. The IMSI stays with the subscription and the ICCID stays with the card or profile.
Answers are revealed on request. Nothing is scored, stored or sent.
FAQ
Does a SIM swap change the IMEI?
Which identifier answers which card is in the box?
Which identifier can move to another operator?
Sources
- ITU-T E.212: The international identification plan for public networks and subscriptions
- ITU-T E.118: Numbering resources for cards to identify accounts for charging telecommunication services
- 3GPP TS 23.003: Numbering, addressing and identification
- GSMA SGP.22 V3.1: Remote SIM provisioning architecture for consumer devices
Terms you'll meet
Related
- Permanent roaming, country by country
How long a foreign SIM may roam before it needs a local profile, for Brazil, Mexico and Colombia, with the decision path to the right product.
- SGP.32 for IoT devices
What SGP.32 changes for IoT fleets, which devices qualify, and why SGP.02 devices cannot be upgraded over the air.
- eUICC identifier (EID)
The eUICC identifier, separate from the subscription.
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