Why did the Mobifone SIM purchased at Hanoi Airport stop working after 6 days?

The Mobifone SIM purchased at Hanoi International Airport suddenly stopped working on the evening of the 6th day. According to the staff at the SIM purchase counter, the cause was a temporary nationwide outage of Mobifone's SIM service at that time.

Which Vietnamese mobile carrier does the staff at the Hanoi Airport SIM purchase counter recommend, and under what circumstances might Mobifone still be chosen?

The SIM counter staff recommended using Viettel instead of Mobifone next time. However, Viettel lacks calling functionality, so Mobifone is chosen when phone functions are needed, such as for calling a Grab or making massage reservations.

How was the issue with the unresponsive Mobifone SIM at Hanoi International Airport resolved?

The staff at the SIM purchase counter within the international airport helped reactivate the SIM, resolving the issue. It was resolved surprisingly easily, so there was plenty of time.

After resolving the SIM issue at Hanoi International Airport, how can one get to the domestic airport?

Exit the international airport, cross the road towards area number 18, and you will find a bus stop for the domestic airport. You can take a shuttle bus from there.

Hanoi Airport SIM Card: My Data Died & How I Fixed It (2026)

Hanoi Airport SIM Card: My Data Died & How I Fixed It (2026) | TRVLOGUE

Planning to spend three weeks exploring Vietnam, I picked up a SIM card at Hanoi Airport. I specifically asked for a one-month plan.

It worked fine. Or rather, it *was* working fine. (Though I did notice some spotty service on the sleeping bus from Hanoi to Sapa).

Then, on the evening of the sixth day after purchasing my SIM at Hanoi Airport, it suddenly died.

What?! Did I accidentally buy a 5-day SIM instead of a month-long one? But it was working perfectly this morning, which is still day six!

Maybe a 7-day plan?

But if it was 5 days, it's 5 days. If it's a week, it's a week. What kind of plan dies on an ambiguous sixth day? (I remember there being 5-day SIMs in Thailand, for instance).

I was so sure I asked for a one-month plan, and I don't recall seeing any 5-day or 7-day options at all.

I wasn't at my hotel at the time; I was out and about.

Suddenly losing data brought everything to a screeching halt.

Without Grab, I was completely stranded.

I really should have just booked an eSIM, which seems to be the popular choice these days.

>> 5G eSIM Vietnam, Viettel

>> Local Data Vietnam eSIM, VINAPHONE

And of course, I was pretty far from my hotel. I ended up having to go back to the cafe I had just left, connect to their Wi-Fi, and call a Grab.

Beyond that, it caused all sorts of major inconveniences and threw my plans into disarray.

I asked the friendly desk staff at my hotel (the same person who helped me fix my suitcase!) if there were 5-day or 7-day SIMs. They confirmed there weren't and assured me a month-long SIM should work without a hitch.

Oh, I was furious. I decided I had to go back to the airport and confront them. Off to Hanoi Airport I went.

Now, I didn't *specifically* go to the airport just for this. (My time is precious, after all!).

My Hanoi leg of the trip was over, and Da Nang was my next destination. (Da Nang wasn't originally planned, but that's a story for another time).

So, I was already in a taxi heading to Hanoi's domestic airport, but the more I thought about it, the angrier I got. (Honestly, the staff member who sold me the SIM was incredibly unfriendly to begin with, which just added fuel to the fire).

So, I changed my destination mid-ride. Well, it was just a switch from the domestic to the international terminal, so not a huge diversion, haha.

The reason being, I bought the SIM from a Vietnamese telecom provider located in the international terminal.

My Grab driver initially kept asking if my destination was really the domestic airport, confirming if it wasn't the international one. I insisted, "No, I'm going to Da Nang, it's domestic!" and we headed there.

But as we were nearing arrival, I suddenly blurted out, "Actually, I need to go to the international terminal!"

A quick tip for travelers: when moving between cities in Vietnam, if you don't specify (especially as a foreigner), drivers will almost always drop you at the international terminal.

So, if you're catching a domestic flight to another city, always emphasize that you need to go to the domestic airport.

Anyway, I arrived at the international airport.

Here I come.

I'm on my way.

Almost there. The shop is on the right.

I confidently walked up to where I bought the SIM and demanded, "This! Why isn't it working?! I bought a one-month plan! Why did it stop after only six days?!"

The cause, it turned out, was that all Mobifone (one of Vietnam's telecom providers) SIMs I purchased had gone dead the night before.

Huh??? Is that even possible? Does that really happen?

(Thinking back, perhaps it wasn't a permanent outage for everyone, but a temporary one. Since I use a dual-SIM phone, I suspect something got tangled up when service returned, causing mine to remain unresponsive).

The staff member actually told me not to use Mobifone next time, and to use Viettel instead, haha. (Another Vietnamese telecom provider...). But as far as I knew, while Viettel is number one, their market share seemed pretty similar.

While writing this post, I actually looked up the market share of Vietnamese telecom companies, haha. Turns out I was wrong! Viettel holds about half the market share.

>> 5G eSIM Vietnam, Viettel

>> Local Data Vietnam eSIM, VINAPHONE

While I was there, I also snapped a picture of the price list. (I didn't take one when I first bought it; again, I wasn't planning to blog then).

However, Viettel doesn't offer call services, which means I'd still probably choose Mobifone.

Why do you need calls, you ask? Well, about 80% of the time you book a Grab, the driver will call you.

(Honestly, I don't know why they call. I've already marked my location and destination on the app... and they must know I'm a foreigner from my name, so Vietnamese won't work unless they speak English... but they call every time... and if I answer in English, they just babble something in Vietnamese and hang up...).

Oh, wait, am I being dumb? Receiving calls probably doesn't matter anyway, haha.

>> 5G eSIM Vietnam, Viettel

>> Local Data Vietnam eSIM, VINAPHONE

Right, let's rethink. It's convenient to call when booking a massage, for example, haha.

Also, if you just hit 'destination' on Grab without confirming your current location, the app sometimes misidentifies where you are, placing you somewhere completely wrong.

Then the Grab driver heads to that incorrect spot, and that's when you need to call them.

(Even if you can't have a conversation, you can at least call and then send a message through the Grab app. But since communication is still tough, it's often easiest to just snap a photo of your current location and send it).

Anyway, I've strayed from the topic. Back to my Hanoi Airport SIM card story.

The staff member kindly got my SIM working again.

Where was that unfriendly employee who sold it to me? Haha, I came all this way to confront *them*!

>> 5G eSIM Vietnam, Viettel

>> Local Data Vietnam eSIM, VINAPHONE

It was resolved much more anticlimactically than I expected... and now I had to go back to the domestic terminal, haha.

Since it was resolved quickly, I had plenty of time. I asked the staff there and headed to the airport shuttle.

Here's the location: