Before you start

Passport, and usually a residence permit or valid visa
A Shenzhen address for broadband
A dual-SIM or eSIM-capable handset, if you want the Hong Kong option
A payment method for top-ups

Step-by-step

1
Get the Chinese SIM in your first days
Any China Mobile, Unicom or Telecom shop issues one against your passport under real-name registration. Prepaid data plans are cheap. Do this before the bank and before flat viewings.
In personWho: YouDay 1–2
2
Register it in your own name, not the company's
An employer-registered number takes your bank verification and payment wallets with it when you leave the job. One extra shop visit removes the whole problem.
In personWho: You
3
Consider a Hong Kong SIM or eSIM in the second slot
Hong Kong numbers roam on mainland networks and Hong Kong operators are not subject to mainland filtering, so a Hong Kong data plan is a widely used, entirely ordinary arrangement in this city. Buying one requires a trip across the border or an eSIM purchase.
Mobile appWho: You
4
Order broadband and check the building first
Chinese fibre is fast and cheap; installation depends on the building's wiring and the landlord's cooperation. Taking over an existing live line in the flat is much faster than a new install — ask at the viewing.
In personWho: You1–2 weeks
5
Sort out access to your critical accounts before you fly
Email, password manager, authenticator, banking. Set the arrangement up and test it while you still have unrestricted access. Ask what your employer provides — in Shenzhen's tech sector this is a normal question.
OnlineWho: YouBefore departure
6
Install the apps the city runs on
WeChat for everything social and much that is official, Alipay for payments, Amap or Baidu Maps for navigation, DiDi for taxis, Meituan and Ele.me for delivery. Google Maps does not work in mainland China.
Mobile appWho: YouWeek 1

Documents you’ll need

Passport
Residence permit or valid visa
Shenzhen address for broadband
Payment method for top-ups

Things most newcomers don’t know

A Hong Kong SIM roaming on mainland networks is the standard local workaround, and it is unremarkable here.

Hong Kong operators are outside mainland network filtering, and Hong Kong numbers roam on mainland towers. The practical result is that a Hong Kong data plan in a second SIM slot or an eSIM gives you a normal internet connection in Shenzhen. This is common enough among Shenzhen residents to be entirely ordinary, and it is one of the concrete advantages of living at this particular border. Data-only roaming plans are the usual form.

Source: community-reported

The Chinese phone number is the root of your identity here, and losing it is expensive.

Real-name registration binds the number to your passport, and from there it becomes the verification anchor for your bank, Alipay, WeChat Pay, hospital bookings, delivery apps and often your compound's door access. Re-establishing it after a lapse means redoing the registration and then re-verifying each downstream service individually. Keep it topped up even through long absences.

Source: Ministry of Industry and Information Technology

WeChat is the address book, the payment rail and the official channel all at once.

Government service accounts, building management, landlords, colleagues, schools and most Chinese businesses operate through WeChat. Declining it means being uncontactable by the people who need to reach you. Set it up before arrival if you can — account verification sometimes needs an existing user to vouch for you, which is easier to arrange from outside China than from a hotel room inside it.

Source: community-reported

Google Maps does not work here, and that is not a preference.

China mandates a coordinate offset on published mapping data, and Google's mainland base data is poor and misaligned. Amap and Baidu Maps are accurate, integrate with the metro and DiDi, and include live transit. Uber does not operate; DiDi does. In a city that has rebuilt itself several times over, an out-of-date map is more than an inconvenience.

Source: community-reported