Quick facts
| eSIM | Pocket Wi-Fi router | |
|---|---|---|
| What it is | A SIM profile downloaded into your phone | A small rented device that makes a Wi-Fi network |
| Devices | Your phone; others through hotspot | Several devices at once (Global WiFi: up to 5 for Vietnam) |
| Extra item to carry | None | Router, and its charger |
| Pick-up and return | None | Collect before the trip, return after it |
| Phone requirement | Unlocked and eSIM-capable | Any device with Wi-Fi |
| Phone number | Only on plans that include one | None |
Disclosure: VietSim sells prepaid eSIMs for Vietnam. We do not rent routers. We describe both so you can decide.
How an eSIM works
An eSIM is the digital version of a SIM card. You buy a plan online, scan a QR code and your phone downloads the profile. When you land, you switch mobile data to that line. Your home SIM stays in the phone, so bank SMS codes still reach you.
Apple lists the iPhone XS, XS Max, XR and later models as eSIM-capable, and an iPhone can store eight or more eSIMs. The phone must not be locked to your home carrier. Step-by-step instructions are in how to install an eSIM.
How a pocket Wi-Fi router works
A pocket Wi-Fi router is a small battery-powered device with a SIM inside. It creates a Wi-Fi network that your phones, tablets and laptops join.
As an example of what rental firms offer, as of September 2026 Global WiFi in Japan lists Vietnam plans from 300 MB a day up to unlimited data. It allows up to 5 devices to connect at once. Customers collect the router at airport counters or lockers in Japan, by home delivery or at Seven-Eleven stores, and return it at the airport or by post. It also sells optional damage cover.
What that means in practice:
- The router has to stay close to everyone who uses it.
- It needs charging, and when its battery runs out, every device loses data.
- It is one more thing to lose, and it has to be returned.
Sharing data from an eSIM
A phone with an eSIM can share its data through Personal Hotspot on iPhone or the hotspot setting on Android. Apple says Personal Hotspot requires a carrier that supports it. The number of devices that can join depends on the carrier and the iPhone model.
For a family where everyone has an eSIM-capable phone, one eSIM per phone avoids depending on a single device.
Relying on hotel and café Wi-Fi
Some travellers skip both and use Wi-Fi where they stay. That works until you need a map in a taxi or a ride app on the street. The US Federal Trade Commission says public Wi-Fi is usually safe because of widespread encryption. It advises checking for https or a lock symbol and staying wary of unfamiliar sites.
Which one fits you
| Your situation | What tends to fit |
|---|---|
| Travelling alone with an eSIM-capable phone | eSIM |
| A group that always moves together, several devices each | Pocket Wi-Fi router, or an eSIM per phone |
| An older phone without eSIM support | Router or a physical SIM card |
| You need a Vietnamese number for SMS codes or calls | An eSIM plan that includes a number |
| Long stay | A local SIM or a longer eSIM plan |
Next steps
Browse plans by network in the Vietnam eSIM store. The networks are compared in Viettel, VinaPhone or MobiFone, and hotspot, 5G and WhatsApp questions are in the Vietnam phone and internet FAQ.