An eSIM not working in China is, in nearly every case, a setting rather than a network problem: data roaming is switched off for the eSIM line, another line is still selected for mobile data, the phone is carrier-locked, or the profile was installed but never activated. The other frequent surprise is not a failure at all: the eSIM connects fine, but Instagram and Google still do not load, because the profile belongs to a Chinese carrier and is filtered like a local SIM. Below, the six checks in the order that resolves most cases, then how to tell which kind of eSIM you actually have.
If your eSIM is fine and it is the VPN that will not connect, that is a different guide: VPN not working in China.
1. Data roaming is on for the eSIM line
A travel eSIM is a foreign carrier's profile visiting China. It only works with data roaming enabled on that line specifically. On iPhone: Settings, Cellular, tap the eSIM line, Data Roaming on. On Android: Settings, Network, SIMs, select the eSIM, Roaming on. Many phones default this to off for a newly added line.
2. The eSIM is the line selected for mobile data
With two lines active, the phone uses one for data. If your home SIM is still the data line, the eSIM sits idle and you pay home roaming rates or get nothing. iPhone: Settings, Cellular, Cellular Data, choose the eSIM. Android: SIMs, Mobile data, choose the eSIM. Turn "allow cellular data switching" off while you are at it, so the phone does not quietly fall back to the other line.
3. The network is selected manually
Travel eSIMs are usually valid on China Mobile or China Unicom, sometimes both. If automatic selection keeps picking a network your profile does not cover, choose it manually: iPhone, Settings, Cellular, the eSIM line, Network Selection, switch Automatic off and pick the carrier; Android, in the same SIM settings. Restart the phone afterwards; after landing, a restart alone fixes a large share of cases.
4. The profile is activated and has data left
Some plans start counting from purchase, others from first connection, and some require a tap in the provider's app or a visit to a link before they go live. Check the provider's app or email for the plan status, remaining data and expiry. Install and activate at home where you have normal internet; the airport is a poor place to discover that activation needed a connection.
5. The phone is unlocked and supports eSIM
Phones bought on installment plans or carrier promotions are sometimes locked to that carrier until the contract ends, and a locked phone will not accept a foreign eSIM. Check with your carrier before travelling. Separately, iPhones sold in mainland China have historically shipped without eSIM support or with limited support; if Settings, Cellular has no "Add eSIM" option, the hardware is the reason.
6. You are actually on the eSIM, not on Wi-Fi or the home SIM
Turn Wi-Fi off, confirm the eSIM shows signal bars and a carrier name, then open What Is My IP. The country shown tells you where your data exits: Hong Kong, Singapore or your home country means the eSIM is roaming as intended; China means you are on a local network.
"It connects, but Instagram still does not load"
That is the second kind of eSIM. A profile issued by a Chinese carrier is a local SIM in digital form: data exits in China and foreign services are filtered, exactly as on a plastic China Mobile SIM. Listings do not always make this obvious, so check whose profile it is before buying; if the description promises foreign apps without a VPN, it is a foreign carrier's profile. With a Chinese eSIM, your usual apps need a VPN that was set up before departure, as described in VPN for China: what to know before you land. The full comparison of roaming, travel eSIM and local SIM is in eSIM, roaming or local SIM in China.
Why a working travel eSIM needs no VPN
Your phone uses the Chinese tower for the radio signal only. Under the roaming agreement, the data is tunneled to the carrier that issued the profile and exits to the internet in that carrier's country. The Chinese gateways see carrier transit, not a user session, and do not filter it. That is routing at the network level, which is why it holds up on days when VPN tunnels do not.
Before you fly
- Install the eSIM at home from the QR code and activate it if the plan requires.
- Set it as the data line, enable data roaming on it, disable automatic data switching.
- Note which Chinese carriers the plan covers, for manual selection.
- Estimate the data you will need with the data usage calculator; turn off app updates and photo backup over mobile data.
- Keep your home carrier's roaming as a fallback, and a VPN configured on top if you also plan to use a local SIM or hotel Wi-Fi.
404 VPN runs over any connection, eSIM, local SIM or Wi-Fi, with VLESS and WireGuard, DNS inside the tunnel, a kill switch and locations in Hong Kong, Singapore, Japan and Thailand. The free plan of 5 GB a day is enough to test before you go. Start on the home page.