Description
The Mobile Country Code (MCC) is a critical, standardized identifier within the global telecommunications numbering plan defined by the International Telecommunication Union (ITU) and adopted by 3GPP. It consists of three decimal digits (e.g., 310 for the United States, 262 for Germany) and serves as the primary geographic identifier for a mobile subscriber. The MCC is permanently encoded into the subscriber's SIM card as the leading segment of the 15-digit International Mobile Subscriber Identity (IMSI), which follows the format MCC-MNC-MSIN. This structure ensures every mobile subscriber worldwide has a globally unique identifier.
Architecturally, the MCC is used at virtually every layer of the mobile network, from the radio interface to the core network. When a mobile device powers on or enters a new area, it scans for available networks and reads the broadcast system information, which includes the MCC and Mobile Network Code (MNC) of each network. The device uses this MCC to determine if it is in its home country (MCC matches the SIM's MCC) or in a visited country (MCC differs). This initial step is crucial for network selection and roaming procedures. Within the core network, specifically in the Home Location Register (HLR) or Home Subscriber Server (HSS), the MCC is a key attribute used to route signaling messages correctly and apply appropriate subscriber profiles and policies.
The MCC works in conjunction with the Mobile Network Code (MNC) to form the PLMN ID (Public Land Mobile Network Identity), which uniquely identifies a specific operator's network within a country. Network elements like the Mobile Switching Center (MSC), Serving GPRS Support Node (SGSN), and Mobility Management Entity (MME) use the PLMN ID (and thus the MCC) for functions like authentication, registration, handovers, and charging. For international roaming, when a subscriber attempts to register on a visited network (VPLMN), the VPLMN uses the MCC from the subscriber's IMSI to identify the home country and then queries the appropriate inter-operator signaling network (like the SS7 or Diameter-based IPX) to contact the home network (HPLMN) for authentication and service authorization.
Its role is foundational to the interoperability and global reach of mobile communications. It enables seamless cross-border mobility by providing a standardized way for networks to identify a subscriber's country of origin. This is essential for routing calls and data sessions, applying roaming agreements, calculating charges, and ensuring lawful interception and emergency services (e.g., determining the correct emergency call center based on the country code). The MCC is a static, administratively assigned code that forms the bedrock of subscriber identity management in all generations of mobile networks, from GSM to 5G.
Purpose & Motivation
The MCC was created to solve the fundamental problem of uniquely identifying mobile subscribers on a global scale, which is a prerequisite for international roaming. In the early days of cellular networks, which were largely national systems, subscriber identification schemes were not globally coordinated. This would have made cross-border communication and mobility impossible, as a visiting network would have no way to identify the home network of a subscriber to retrieve authentication data and billing information.
The primary motivation was to establish a worldwide numbering plan that would allow for the unambiguous identification of a subscriber's country of registration. This addressed the critical need for interoperability between different national networks operated by different carriers. The ITU, in recommendation E.212, defined the structure of the IMSI and allocated the MCC ranges to countries. 3GPP adopted this standard, ensuring that every SIM card produced anywhere in the world contains a globally unique IMSI, starting with the MCC.
Historically, its introduction with GSM (from R99 onwards) was a key enabler for the 'global' in Global System for Mobile Communications. It solved the limitations of purely national numbering plans and allowed for the automated, secure handling of roaming subscribers. Without the MCC, the complex web of bilateral roaming agreements that underpin today's mobile experience would be unmanageable. It remains a cornerstone of mobile identity, supporting everything from basic voice roaming to the sophisticated home-routed traffic models used in 4G and 5G data roaming.
Classification
Release Timeline
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (58 CRs across 6 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the primary updates to the Mobile Country Code (MCC) function were editorial in nature and focused on the correction and publication of the specification text. This included a specific correction to the implementation of a prior Change Request and general editorial updates following formal approval by the responsible technical group. The updates ensured the MCC's role in defining network identities, such as the Home PLMN and Visited PLMN, remained clearly documented within the framework of PLMN identification.
- Update to Rel-15 version (MCC) TS 23.251
- MCC Editorial update for publication after TSG SA approval (SA#76) TS 23.782
- Update to Rel-15 version (MCC) TS 24.103
- Update to Rel-15 version (MCC) TS 25.367
- Update to Rel-15 version (MCC) TS 32.270
- Update to Rel-15 version (MCC) TS 32.272
+ 1 more changes
In Release 16, the primary update for the Mobile Country Code (MCC) function was the addition of new general abbreviations to the specifications. Furthermore, a key functional enhancement was introduced, allowing for the USIM configuration of an allowed MCC list specifically for RLOS (Radio Link Outage Supervision). Other listed changes consisted of routine updates to bring the relevant MCC specification texts to the Release 16 version.
- Add new general abbreviations MCC Note: CR cover sheet wrongly shows CR number as "1118". TS 21.905CR0118
- USIM configuration of RLOS allowed MCC list TS 31.102CR0881
- Updated to Rel-16 by MCC TS 22.022
- Update to Rel-16 version (MCC) TS 23.251
- Update to Rel-16 version (MCC) TS 24.103
- Update to Rel-16 version (MCC) TS 25.931
+ 6 more changes
In Release 17, the primary update to the Mobile Country Code (MCC) function was a series of maintenance and version alignment updates, as indicated by the multiple Change Requests titled "Update to Rel-17 version (MCC)." The technical grounding shows these included a correction to a previous CR implementation and an editorial update, ensuring the specification text accurately reflects the MCC's role in defining Home PLMNs, Visited PLMNs, and network codes for procedures like inter-PLMN handover.
- Updated to Rel-17 by MCC TS 22.022
- Update to Rel-17 version (MCC) TS 23.251
- Update to Rel-17 version (MCC) TS 24.103
- Update to Rel-17 version (MCC) TS 24.305
- Update to Rel-17 version (MCC) TS 26.223
- Update to Rel-17 version (MCC) TS 26.923
+ 4 more changes
In Release 18, the primary update for the Mobile Country Code (MCC) function was an administrative version update to align the specification with the new release baseline, as indicated by the recurring "Update to Rel-18 version (MCC)" Change Requests. This process included a correction to a previous implementation and an editorial update, ensuring consistency within the network identity parameters used for defining Home PLMNs, Visited PLMNs, and handover types. The update maintained the core technical role of the MCC, which, combined with the MNC, continues to uniquely identify a PLMN for critical procedures like inter-PLMN and intra-PLMN handover.
- Update to Rel-18 version (MCC) TS 21.905
- Updated to Rel-18 by MCC (and issue with v.18.0.0 upload) TS 22.022
- Update to Rel-18 version (MCC) TS 23.251
- Update to Rel-18 version (MCC) TS 24.103
- Update to Rel-18 version (MCC) TS 24.305
- Update to Rel-18 version (MCC) TS 25.931
+ 8 more changes
In Release 19, the primary update for the Mobile Country Code (MCC) function was an editorial and maintenance update to align the specification with the new release version. This involved incorporating corrections from a previous Release 18 Change Request implementation, specifically for MCC, and updating all relevant instances within the document to the Release 19 baseline. The changes were procedural, ensuring the technical descriptions of PLMN identities, which are defined by MCC-MNC pairs, remained accurate and consistent across the specification.
- Updated to Rel-19 by MCC TS 22.022
- Update to Rel-19 version (MCC) TS 23.251
- Update to Rel-19 version (MCC) TS 24.103
- Update to Rel-19 version (MCC) TS 24.305
- Update to Rel-19 version (MCC) TS 25.931
- Update to Rel-19 version (MCC) TS 26.118
+ 8 more changes
In Release 20, the primary update for the Mobile Country Code (MCC) function was an editorial update for publication following TSG SA approval. This included a correction to the implementation of a previous Change Request and general maintenance to ensure the specification text was current and accurate. The update did not introduce new technical procedures or capabilities related to MCC's role in network identities, handovers, or PLMN definitions.
- MCC Editorial update for publication after TSG SA approval (SA#109) TS 23.700
Explore further
Broader topics and technologies where MCC plays a role.
Defining Specifications
3GPP specifications that define or reference MCC, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TR 21.905 vj00 | 3GPP Technical Terms and Definitions | Rel-19 |
| TS 22.022 vj00 | ME Personalisation Features for GSM/3G | Rel-19 |
| TR 22.975 v1310 | UMTS Numbering and Addressing Requirements | Rel-4 |
| TS 23.251 vj00 | Network Sharing Stage 2 Specification | Rel-19 |
| TS 23.700 vk00 | XR Services Application Enablement Layer | Rel-20 |
| TS 23.782 vf00 | Interworking between LTE MC and non-LTE MC systems | Rel-15 |
| TS 23.851 v1600 | Network Sharing Architecture for 3G Systems | Rel-6 |
| TS 24.103 vj00 | Telepresence Protocol for IMS | Rel-19 |
| TS 24.229 vj50 | IMS call control protocol based on SIP and SDP | Rel-19 |
| TS 24.235 vc10 | I-WLAN Interworking Management Object | Rel-12 |
| TS 24.305 vj00 | Selective Disabling of 3GPP UE Capabilities | Rel-19 |
| TS 24.526 vj30 | UE Policies for 5GS; Stage 3 | Rel-19 |
| TS 25.304 vj00 | UTRA Idle Mode Procedures Specification | Rel-19 |
| TS 25.331 vj00 | UTRAN RRC Protocol Specification | Rel-19 |
| TS 25.367 vj00 | Home NodeB Mobility Procedures | Rel-19 |
| TR 25.931 vj00 | UTRAN Signalling Procedures Examples | Rel-19 |
| TS 26.118 vj00 | Virtual Reality Media Formats | Rel-19 |
| TS 26.223 vj00 | IMS Telepresence Client Specification | Rel-19 |
| TR 26.923 vj00 | Study on IMS-based Telepresence Media Handling | Rel-19 |
| TR 26.929 vj00 | QoE Metrics for VR Services Study | Rel-19 |
| TR 26.939 vj00 | Framework for Live Uplink Streaming (FLUS) | Rel-19 |
| TR 29.949 vj00 | VoLTE IMS Roaming Architecture & Procedures | Rel-19 |
| TS 31.102 vj40 | USIM Application Specification | Rel-19 |
| TS 31.121 vi50 | UICC-terminal interface test specification | Rel-18 |
| TS 32.251 vj00 | PS Domain Charging Management | Rel-19 |
| TS 32.270 vj00 | MMS Charging Management Specification | Rel-19 |
| TS 32.272 vj00 | Charging for Push-to-Talk over Cellular (PoC) | Rel-19 |
| TS 32.277 vj20 | Charging Management for Proximity Services (ProSe) | Rel-19 |
| TS 32.293 vj00 | Proxy Function in Domestic Service Provider | Rel-19 |
| TS 32.298 vj30 | Charging Data Record (CDR) Parameter Specification | Rel-19 |
| TS 32.849 vd00 | IMS Roaming Charging Study | Rel-13 |
| TS 36.304 vj00 | UE Idle Mode Procedures in E-UTRA | Rel-19 |
| TS 38.304 vj00 | UE RRC_IDLE and RRC_INACTIVE Procedures | Rel-19 |
