3G is the third generation of mobile networks (UMTS, CDMA2000), launched in 2001, which brought mobile internet and video calls to phones.
How 3G works
3G networks follow the ITU’s IMT-2000 requirements. In Europe and most of the world they were built on UMTS/WCDMA, in North America partly on CDMA2000. Upgrades such as HSPA and HSPA+ pushed download speeds from a few hundred kbit/s to tens of Mbit/s. The first commercial network was opened by NTT Docomo in Japan in 2001.
Why 3G matters for security
3G fixed a major weakness of 2G (GSM): the subscriber and the network now authenticate each other (AKA protocol), which makes simple fake base stations harder to run. However, attackers can still force phones to fall back to 2G with an IMSI catcher, and 3G core networks rely on the old SS7 signalling system, which has been abused to track phones and intercept SMS one-time codes.
Today 3G is being switched off: operators in the US, Germany, the UK and many other countries have already shut down their 3G networks to reuse the spectrum for 4G and 5G. Devices and IoT modules that only support 3G lose connectivity, which matters for alarm systems, trackers and emergency buttons.
What to keep in mind
- Do not rely on SMS codes sent over mobile networks as your only second factor; use app-based or hardware MFA.
- Check that security devices (alarms, GPS trackers, lift phones) support 4G/LTE-M before 3G shutdown dates.
- On Android, disabling 2G in network settings reduces exposure to downgrade attacks.
