Difference between SIM and USIM.

The most common types of subscriber identification cards from cellular operators are products such as SIM and USIM. What are they?

Facts about SIM-cards

SIM is a traditional standard on the basis of which identification cards of subscribers of mobile networks work. Most of all, it is widespread in those countries where the provision of cellular services is carried out via GSM channels.

SIM cards are protected by several types of codes - PIN and PUC. By default, entering the first one from the phone is mandatory for the subscriber to gain access to the network. But the user can, if he wishes, and disable it. The PUC code is used to unlock a SIM card in which the PIN is entered incorrectly 3 times in a row.

Facts about USIM-cards

USIM is another widespread standard on the basis of which the cards of identification of subscribers of cellular operators function. It is most popular, in turn, in those countries where mobile services are provided in networks such as UMTS (that is, with 3G Internet). In fact, it is an extended modification of the SIM standard, which is adapted to work in high-speed networks of the corresponding type. Thus, USIM can support GSM frequencies as well. As is the case with SIM cards, products in USIM format are protected by codes - PIN and PUC.


The main difference between SIM and USIM is in the level of manufacturability, as well as in its adaptation to the UMTS communication standard. Traditional SIM cards are designed primarily to meet the needs of subscribers for voice communications and sending SMS messages. USIM cards are designed for people who regularly use, along with "classic" communication services, and the mobile Internet.

The main advantages of USIM over SIM:

  • It is theoretically possible to write various miniature applications to the internal memory of the USIM;
  • USIM cards are better adapted for video calling from a phone on 3G networks;
  • support for more advanced cryptographic security standards;
  • the ability to record several thousand contacts in the internal phone book (while in a regular SIM card - up to 255);
  • the ability to record in contacts entered in the internal phone book, e-mail, as well as additional subscriber numbers.

In terms of size, both types of cards are the same and therefore can fit in the same phones. Provided, of course, that the device will support the USIM standard.

It should be noted that when selling USIM-cards in communication salons, the fact that they are USIM is often not advertised. People habitually call them SIM cards, because in general, the functions of both are the same, and their appearance is also not too different. Therefore, when registering an account in a communication salon, it is better to immediately clarify what type of card the operator is issuing. Although, of course, in most cases it will be USIM, since almost all modern networks in Russia are 3G, moreover, they are already being actively replaced by 4G networks.

Having determined what is the difference between SIM and USIM, we will enter the key criteria in a small table.


SIM cards USIM cards
What do they have in common?
Same size
Supports security PIN and PUC codes
USIM cards support all the standards in which products in the SIM format can operate
What is the difference between them?
Do not allow applications to be placed in internal memoryAllow applications to be placed in internal memory
Not always optimal for work in 3G networksCreated for work in 3G networks
Have less reliable cryptographic protectionHave more reliable cryptographic protection
Supports writing to the internal memory of up to 255 contactsSupports writing to the internal memory of several thousand contacts (with e-mail and additional subscriber numbers)