Option 1 - Roaming: easiest, works on landing, no SIM change; costs more (about RMB 30/day) and some carriers still block foreign sites.
Option 2 - Local SIM: China Mobile/Unicom/Telecom foreigner plans give the best value, e.g. 100-200 yuan a month with tens of GB; passport needed for real-name registration.
Option 3 - Pocket Wi-Fi: good for groups, rentable at airports (20-40 yuan/day); needs charging and depends on carrier signal.
Choosing: over 5 days, get a local SIM; 2-3 days, roaming is fine; 3+ people sharing, a pocket Wi-Fi wins.
Reminder: local SIMs are tied to your passport; cancel or confirm auto-expiry before leaving to avoid unpaid bills.
