PLMN stands for Public Land Mobile Network. It's a 5 or 6 digit code that uniquely identifies a mobile network globally. Every time your phone connects to a tower, it's connecting to a specific PLMN.
Structure
A PLMN code is made of:
- MCC (Mobile Country Code) — 3 digits. UK = 234.
- MNC (Mobile Network Code) — 2 or 3 digits.
UK PLMNs
- EE: 234-30
- O2: 234-10
- Vodafone: 234-15
- Three: 234-20
Why it matters
Multi-network and roaming-capable SIMs use PLMN lists to decide which networks they're allowed to connect to. When you travel, your phone scans for PLMNs your carrier has roaming agreements with. When you're home on a multi-network plan like Fuse, your phone picks the strongest PLMN from the carrier's allowed list.