My friend Raj from Mumbai came to China for a conference. He had international roaming on his Jio SIM. He thought: "I'll just use roaming. Why bother with a Chinese SIM?"
Day 1:
Landing at Beijing Capital. Raj turns on his phone. Signal: 1 bar. 3G.
He tries to load WeChat. It loads... eventually. He tries to load Google Maps. It doesn't load. He tries to load his email. It times out.
"It's fine," he tells himself. "I'm just at the airport. It'll be better in the city."
Day 2:
In the city. Signal: 2 bars. Still 3G.
Raj realizes that while his phone "works," everything is unbearably slow. Apps take 30 seconds to open. Maps don't load in time. His VPN (which he needs for work email) can't maintain a connection on 3G.
He tries to video call his wife. The call drops three times. She texts him: "Are you in a bunker?"
Day 3:
Raj goes to a China Unicom store. Buys a local SIM. ¥100 for 20GB.
Puts it in his phone.
5G. Full bars. Everything loads instantly.
His reaction:
"I spent three days living like it was 2009. This SIM just gave me my life back."
The technical explanation:
International roaming in China often connects to older networks (3G/4G) because your home carrier doesn't have full agreements with Chinese 5G networks. Plus, roaming data routes through your home country before coming back, which adds massive latency.
A local SIM connects directly to China Mobile/Unicom/Telecom's 5G network. No routing delays. Full speed.
Kurokun's advice:
If you're staying more than 3 days, just get a local SIM or eSIM. Don't rely on roaming.
If you're staying under 3 days, an eSIM (Airalo, Holafly) is better than roaming because it connects directly to local networks.
Raj now tells everyone: "The first thing you do at the airport is buy a SIM. Before you get coffee. Before you find your hotel. Buy the SIM."
Posted on 2026-5-23 07:56:38