# Identity: four numbers and an eUICC ID

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.

- 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.

## 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

The panel decodes the ICCID in the box and shows the industry identifier, the issuer and account part, the check digit and the check result. The identifier toolkit decodes the IMSI, IMEI and EID with the same parsers.

Alt: An input box holding a 19-digit ICCID, with labeled fields for the industry identifier, issuer and account, check digit and validity.

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.

| Item | Value | Note |
| --- | --- | --- |
| Industry identifier | 89 |  |
| Issuer and account | 9900000000000000 |  |
| Check digit | 5 |  |
| Check | Valid |  |

Source: ITU-T E.118 and ITU-T E.212: identifier structure (https://www.itu.int/rec/T-REC-E.118/en)

## 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

|  | 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](/en/tools/mcc-mnc/) 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](/en/tools/identifier-toolkit/) checks the structure and the check digits in the browser.
The [MCC-MNC lookup](/en/tools/mcc-mnc/) names the network that owns a PLMN; it is not a blame tool. The [phone validator](/en/tools/phone-validator/) checks a number's structure, not whether it is reachable. For the profile side, read [what an eSIM is](/en/resources/learn/what-is-esim/) and [what multi-IMSI does](/en/resources/learn/what-is-multi-imsi/).

The sample is documentation-safe. Your value stays in the browser.

[Open the tool](/en/tools/identifier-toolkit/?src=learn-four-numbers-imsi-iccid-imei-msisdn&scenario=decode-iccid&sample=8999000000000000005)

### A SIM swap is not a device swap

Myth: a new SIM means a new device identity.
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.

## FAQ

**Does a SIM swap change the IMEI?**

No. The IMEI belongs to the device. A swap changes the ICCID and may change the IMSI; the device keeps its IMEI.

**Which identifier 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 the box.

**Which identifier can move to another operator?**

The MSISDN, under portability. The IMSI stays with the subscription, and the ICCID stays with the card or profile.

## Sources

- [ITU-T E.212: The international identification plan for public networks and subscriptions](https://www.itu.int/rec/T-REC-E.212/en) — Accessed: 2026-10-19
- [ITU-T E.118: Numbering resources for cards to identify accounts for charging telecommunication services](https://www.itu.int/rec/T-REC-E.118/en) — Accessed: 2026-10-19
- [3GPP TS 23.003: Numbering, addressing and identification](https://www.3gpp.org/ftp/Specs/archive/23_series/23.003/) — Accessed: 2026-10-19
- [GSMA SGP.22 V3.1: Remote SIM provisioning architecture for consumer devices](https://www.gsma.com/solutions-and-impact/technologies/esim/gsma_resources/sgp-22-v3-1/) — Accessed: 2026-10-19

Updated: 2026-10-19