However, I did need to keep my UK mobile number for a number of important reasons — mainly things like my UK bank accounts, credit cards and HMRC. Occasionally they send a OTP (one-time password) to verify your identity when logging in or making changes.

So before leaving the UK I switched networks and purchased a Lebara monthly physical SIM plan with 5GB of data for £5 per month. I transferred my existing UK mobile number from EE to Lebara and kept that SIM active.

Vietnamese SIM Card Quick Summary

If you're moving to Hanoi or staying long-term, here is the quick version of what worked for me:

Major mobile networks: Viettel, Vinaphone and Mobifone

Typical cost: about £30–£40 for a six-month plan

Data allowance: often several GB per day

Passport required to register a SIM

Having a local Vietnamese number makes it easier to use apps like Grab, Zalo and Shopee

It’s still worth keeping your UK number active for bank OTP verification codes

My Temporary SIM When I Arrived

Someone back home kindly bought me a two-week Vietnam eSIM as a retirement present, so I activated that as soon as I landed at Noi Bai Airport in Hanoi. This meant I had mobile data immediately and didn’t need to rush around looking for a Vietnamese SIM card on my first day.

During my first couple of weeks, I visited a few phone shops and looked online to compare different options before deciding what was best.

Choosing a Vietnamese SIM

I eventually decided on a physical SIM plan with Viettel, which is one of the largest and most reliable mobile networks in Vietnam.

The plan I chose included:

• 6GB of data per day

• 100 minutes of calls per month

• A Vietnamese phone number

The cost was 1,130,000 VND for six months, which worked out at roughly £33 in total.  Compared to UK mobile prices, that felt incredibly cheap.

Setting It Up

Before leaving the UK I had planned ahead and changed my phone to one that supported dual physical SIM cards, specifically so I could run both my UK and Vietnamese numbers at the same time.

When you buy a SIM card in Vietnam, you need to take your passport into the shop so they can register it properly.

I paid for the plan, handed my phone to the shop assistant, and she set everything up and activated it for me. The whole process only took about ten minutes.

Why Having a Vietnamese Number Helps

Having a local Vietnamese phone number turned out to be very useful.  It allowed me to sign up for several important local apps, including:

• Zalo – similar to WhatsApp and widely used across Vietnam

• Grab – the equivalent of Uber, used for taxis, motorbike rides and food delivery

• Shopee – essentially the Vietnamese version of Amazon

Without a local phone number, using some of these services can be more difficult.

What I Did During Visa Run

Because I stay in Vietnam on 90-day tourist visas, I occasionally have to leave the country for visa runs.

When flying to somewhere like Thailand, I simply buy a Thai SIM card at the airport and temporarily swap it with my Vietnamese SIM. When I return to Hanoi, I just switch back again.  It is a simple system that works well.

When I Had to Change My Setup

This setup worked perfectly for about nine months.  Then one day I dropped my phone and cracked the screen. That gave me the excuse to upgrade and I bought a new Google Pixel 9 in Hanoi.  The only problem was that the new phone didn’t support two physical SIM cards.  So I adapted the setup slightly.

I converted my Lebara UK SIM to an eSIM, which meant I could keep my UK number digitally installed on the phone.

Now I run my Viettel Vietnamese physical SIM for everyday use in Vietnam. But when I need to deal with my UK bank or other companies back home, I simply activate the Lebara eSIM so I can receive any OTP verification codes they send.

It’s a simple system that works very well.

Final Thoughts

If you’re moving to Vietnam for any length of time, I would definitely recommend getting a local Vietnamese SIM card.

The plans are extremely affordable, the data allowances are generous, and having a local number makes everyday life — and using local apps — much easier.

At the same time, it’s still worth keeping your UK number active, even on a cheap plan, because many UK companies still rely on sending verification codes by text.

Having both numbers available has worked perfectly for me.