Taiwan slows 4G and 5G for 30 minutes in first-ever communications blackout drill

Taiwan has for the first time deliberately slowed mobile internet speeds during its annual civil defense exercises. Data transmission rates on 4G and 5G networks were reduced for 30 minutes to simulate a communications failure. Phone calls, SMS messages, and the public alert system continued to operate normally throughout the drill.

The exercise took place on August 10 in the central part of the island, affecting Miaoli, Taichung, Changhua, Nantou, Yunlin, Chiayi counties and Chiayi City. Residents in these areas could still use wired cable internet and Wi-Fi, as those channels remained available. Organizers said that during the drill in Taichung, only core mobile services were active, while ATMs, traffic lights, landline phones, and fixed internet were unaffected.

The next phase is scheduled for August 13 and will cover the northern region: Taipei, New Taipei, Taoyuan, Keelung, Hsinchu, as well as Hsinchu and Yilan counties. In total, August restrictions are expected to affect 14 cities, home to about 70% of Taiwan's population.

Authorities had warned citizens in advance, including via social media, so most residents were prepared for the temporary disruption.