What SD135 actually is
SD135 is a plan code quoted exactly as a Vietnamese carrier sells it, in the same family as codes like V90B. It belongs to the informational mobile plan catalogue on VietSIM, which exists for Vietnamese subscribers comparing domestic plans, not for visitors.
That distinction matters because travellers searching for "SD135" often assume it is something they need to arrange before a trip. It is not a visa, an arrival card, a travel authorisation or an eSIM SKU. It is an internal carrier reference.
If you are a Vietnamese subscriber, the matching plan page in the catalogue is where you compare it. If you are a visitor, the rest of this article is for you.
Why travellers keep landing on plan codes
Vietnam's mobile market is dense. Three networks dominate, each with dozens of prepaid and postpaid plans, and each plan has a short code. Search engines surface those codes to anyone typing "Vietnam SIM" or "Vietnam data", which is how a domestic plan code ends up in a traveller's search bar.
The practical fix is to separate the two questions:
- For Vietnamese residents: which carrier plan gives the best local voice and data bundle at the best monthly price? That is a catalogue question.
- For visitors: which prepaid eSIM gives me data from the moment I land, without a shop visit? That is a store question.
This article answers the second one. For the first, the catalogue page for the specific code is the right destination.
What to buy instead: the Vietnam eSIM
A prepaid Vietnam eSIM is a data plan you install on your phone before departure. It activates when it connects to a Vietnamese network on arrival. There is no plastic to swap, no queue at the airport counter, and no need to hand over your passport for a tourist SIM.
The VietSIM store is here: Buy the Vietnam eSIM.
What to check before you buy:
- Phone compatibility. Your handset must be eSIM-capable and carrier-unlocked. iPhone XS and later, most recent Samsung Galaxy and Google Pixel models qualify, but the list is not universal.
- Trip length. Match the plan's validity to your days on the ground. A 10-day plan on a 14-day trip leaves you topping up.
- Data volume. Navigation, messaging and booking apps are light. Video calls, cloud photo backup and hotspot tethering are not.
- Network. The plan's product record states which Vietnamese network it uses. Read that line rather than assuming.
Decision table: which option fits your trip
| Situation | Best fit | Why |
|---|---|---|
| Short trip, 3–7 days, one phone | Prepaid Vietnam eSIM | Installs before you fly, activates on landing, no shop visit |
| Two weeks, heavy maps and messaging | Larger-data Vietnam eSIM | Avoids mid-trip top-ups |
| Working remotely, video calls daily | High-data eSIM plus hotel Wi-Fi | Mobile data alone gets expensive fast |
| Travelling with a laptop | eSIM plus hotspot tethering | Check the plan allows tethering before relying on it |
| Staying a month or more | Compare eSIM against a local prepaid SIM | Long stays can favour a local SIM bought in-country |
| Vietnamese resident comparing plans | The catalogue plan page | Domestic plans are priced and sold differently |
Getting set up before you fly
Installation is the step people skip, and it is the step that causes most first-day problems. Do it at home, on Wi-Fi, while you still have a stable connection and time to troubleshoot.
- Install the eSIM profile before departure, but do not switch it on until you land.
- Keep your home SIM active for banking and two-factor codes if your phone supports dual-SIM.
- Screenshot your plan details and the QR code before you leave.
- If the eSIM does not connect after landing, toggle airplane mode once, then check the APN settings.
For a full walkthrough, see Vietnam eSIM activation.
Device-specific notes
Most setup problems are device problems, not network problems. Two guides cover the common cases:
- Android: Vietnam eSIM for Android covers compatibility, APN entry and the phones that work.
- iPhone: Vietnam eSIM for iPhone covers dual-SIM behaviour and keeping WhatsApp on your home number.
If you plan to share your connection with a laptop or a second phone, read Vietnam eSIM as a hotspot first. Tethering rules vary by plan, and hotspot use burns data faster than phone-only browsing.
Arriving: what to expect at the airport
You do not need to buy anything at the airport if your eSIM is already installed. That is the main advantage: you walk past the SIM counters and switch your data line on.
If you have not arranged an eSIM and want to compare the on-arrival options, the airport guides cover prices and opening hours:
- Tan Son Nhat Airport SIM card for Ho Chi Minh City
- Noi Bai Airport SIM card for Hanoi
- Da Nang Airport SIM card for central Vietnam
Airport counters are convenient but priced for convenience, and late-night arrivals often find them closed. An eSIM removes that variable.
Network coverage in practice
Vietnam's three main networks cover the populated areas well, including the main tourist corridors. Coverage thins in mountains, on remote islands and inside some karst terrain.
For a network-level comparison, see Viettel, VinaPhone or MobiFone. For where 5G is actually live, see 5G in Vietnam.
Do not assume a plan's speed or coverage beyond what its product record states. If a specific network matters to your itinerary, check the plan page before buying.
If you have already lost your order link
Order links arrive by email. There is no public order lookup page, so if you cannot find the email, go to the help centre and follow the contact route there. Do not buy a second plan before checking.