A physical SIM card bought on arrival is the safest bet. eSIMs do work, and some guests use them with no trouble — but on some of them certain functions don't connect, and receiving an SMS is the one that bites. Almost every sign-up on your phone, payment apps included, verifies you by text. If you have neither a SIM nor an eSIM, you can still get online, but expect to spend the first hour of the trip solving it rather than enjoying it.
The three options, in the order I'd rank them
1. A physical SIM card from a Chinese carrier. Bought on arrival with your passport — the airport and the carrier shops in any city will do it. This is the option that behaves exactly like a normal phone: calls, data, and text messages that actually arrive.
2. An eSIM. Convenient, and it means you can sort it out before you fly. It works for data. The caveat is the one above: some eSIMs won't receive SMS properly, and a number that can't receive a text is a number that can't verify you for anything. If you go this route, test that messages actually arrive before you depend on it.
3. Nothing. Plenty of people arrive with an unconnected phone and sort it out over the first day. It is survivable. It is just not the way to start a trip that begins with a long drive out of the city.
Why the text message is the thing that matters
Data gets the attention, but the SMS is what actually decides how smooth your trip is. Nearly every service you will want to set up — the two payment apps above all — confirms your identity with a code sent by text. If your eSIM doesn't deliver that message, you don't get the code, and the whole chain stops there.
That is the entire argument for a physical SIM. It is not that the data is faster. It is that it answers the phone when something asks it to.
Set things up before you fly
Two things are worth doing at home rather than at the airport. First, install and register your payment apps — see how to set them up step by step. Second, be aware that Google and a number of Western apps do not work here by default, so anything you rely on daily is better replaced or arranged before you leave.
Hotel Wi-Fi is common and normally free, which covers the evenings. It does not cover the car, the high passes, or the village guesthouse — and on this trip, that is where a lot of the day is spent.
Questions I get on this one
Does an eSIM work in China?
Do I need a Chinese phone number?
What about just using my own SIM on roaming?
Is the Wi-Fi in hotels good enough?
Written from living and working here rather than from a guidebook. Related: setting up Alipay and WeChat Pay · how you pay for things · all essentials