Can You Use a US SIM Card in China? Calls, Texts and Verification Codes Explained

2026-11-13

The short answer: yes. China is on T-Mobile's roaming coverage list, so you can take calls and receive SMS verification codes there. Data depends on your plan tier, and prepaid plans generally get no data roaming in China. Confirm your plan and turn on Wi-Fi Calling before you leave, and your number stays reachable.

1. What your US SIM can still do in China

• Calls and texts: with a plan that includes China roaming, your phone connects to a local partner network and you can make and receive calls and texts. Bank and email verification codes arrive as usual.
• Data: roaming data routes through your US carrier, which often makes some overseas apps load more smoothly — but once your high-speed allowance runs out, speeds drop sharply, so don't rely on it as your main connection.
• Split the job: use a Chinese SIM for data and daily calls, and keep the US SIM just for verification codes. That's the cheapest and most reliable setup.

2. T-Mobile in China: what it costs

• Texting is free: most postpaid plans include unlimited texting in China. Calls run about $0.50 per minute.
• High-speed data depends on your plan: mid- and top-tier plans include 5GB or 15GB of high-speed roaming data, then throttle to around 256kbps. Lower-tier plans get no free high-speed data.
• Top up if you need more: T-Mobile sells International Passes for 1, 10, and 30 days with high-speed data and unlimited calling. Confirm the current price at the time of purchase.
• Prepaid warning: prepaid plans generally have no international data roaming — in China they can call and text, but data needs Wi-Fi or a Chinese SIM.

3. Not receiving codes? Turn on Wi-Fi Calling

• How it works: Wi-Fi Calling lets your phone make calls and send texts over Wi-Fi, with no cellular signal needed. It works in China too.
• Setup: on iPhone, go to Settings → Phone → Wi-Fi Calling and switch it on. On Android, look for the Wi-Fi Calling toggle in call settings. When "Wi-Fi Calling" appears in the status bar, you're connected.
• Do it before you fly: first-time activation is best done while you're still in the US on your home network — activating from China can fail because the carrier's confirmation text can't reach you.
• If codes still don't arrive: check that the plan is paid up, the phone is on Wi-Fi, and Wi-Fi Calling is switched on, then request the code again.

4. Staying in China long term: keeping your number

• Roaming is for trips, not relocation: carrier terms say roaming is meant for short travel, and heavy long-term use abroad can be restricted or shut off.
• Keep paying on time: if the plan lapses and the number is cancelled and recycled, accounts tied to it become very hard to recover.
• Pick a cheap plan to keep the number: if you only need verification codes, the cheapest plan that keeps the number active is enough — use a Chinese SIM for data.

5. Before-you-fly checklist

• Confirm your plan includes roaming in China, and ask how texts, calls, and data are billed.
• Turn on data roaming and Wi-Fi Calling, and test receiving a text while still in the US.
• Check the plan's expiry date and make sure you can renew it from China.
• Set up dual SIM properly: the US line as the default for verification codes, the Chinese line as the default for data.