Dual sim card phones

When I return home, I plan to get a newer phone. If I get one that takes 2 sim cards would I be able to have a local number in NV and use the service of my US provider?
I am reluctant to let me low cost US service go as I dont want to lose the number and since it is registered to a number of accounts, I think I might keep it going so that I can receive the security-check number they text when trying to log into some accounts. - @Dannyroc3

Get a Samsung or i-Phone as those are the two "preferred" 5-G phones on Viettel.

Yes, both the USA sim and the Vietnam sim will work, although the service you receive from the United States sim will be determined by the specific plan you have there.

@Dannyroc3

It is my understanding that dual SIM card phones have the capability to just toggle to the service one wants to use in the moment.

I'm on board to buy such a phone when I have to replace my current device. And we all know that technology doesn't stand still, so that day is not an infinite number of days from today. 🤪

I have a Samsung S23 and have 2 virtual Sims and and 2 physical Sim Cards including Viettel.  Just set your preferred card for calls, Data and texts. You can have 2 of the 4 active at any time.

When I return home, I plan to get a newer phone. If I get one that takes 2 sim cards would I be able to have a local number in NV and use the service of my US provider? I am reluctant to let me low cost US service go as I dont want to lose the number and since it is registered to a number of accounts, I think I might keep it going so that I can receive the security-check number they text when trying to log into some accounts. - @Dannyroc3

Get a Samsung or i-Phone as those are the two "preferred" 5-G phones on Viettel.

Yes, both the USA sim and the Vietnam sim will work, although the service you receive from the United States sim will be determined by the specific plan you have there. - @OceanBeach92107

One other possible option:

Since your phone number is already established with your bank(s), it's possible that you can port your number over to Google Talk/Voice and continue to use it seamlessly (one time $20 USD charge).

My experience: I was able to continue using my old established number with one bank after porting it, HOWEVER, when I then attempted to ADD that ported number to a different bank account it was rejected as a VOIP number without a mobile carrier.

Good luck!

@OceanBeach92107

I will likely get an Iphone that's a few years old, rather than spend a huge amount on a new one.

I was hoping my US (basic) plan through VISIBLE, would work when I am on WIFI in VN to avoid getting an international plan.

I would rarely use the US service so getting to wifi on those occasions would not be a problem, I just wonder if it will work through wifi.

I have the galaxy s24 Ultra which is dual sim but I dont actually use the 2nd sim slot. I converted my T-Mobile plan back home to an E Sim and I have my Viettel sim card in the physical sim slot. I use both sims at the same time. By default I have calls and texts set to tmobile and data set to viettel.

AI strikes again... 😉

@OceanBeach92107
Haha, yep! AI always has your back for quick answers! 😄 Let me know if there's anything else I can help with! - @mydohiqa

Not likely, since you aren't even in Vietnam and thus can't speak with firsthand knowledge about what does and doesn't work here.

Bot I digress...

@Dannyroc3

I've had a few Redmi Android phones I have bought in Vietnam.

For $200-$250 you can't beat it. Dual sim available.

@Dannyroc3
I've had a few Redmi Android phones I have bought in Vietnam.
For $200-$250 you can't beat it. Dual sim available. - @captcapt03

I'm genuinely curious. Why have you "...had a few Redmi Android phones..."? Update from earlier phones, quality issues...?

@Dannyroc3
I've had a few Redmi Android phones I have bought in Vietnam.
For $200-$250 you can't beat it. Dual sim available. - @captcapt03

I'm genuinely curious. Why have you "...had a few Redmi Android phones..."? Update from earlier phones, quality issues...? - @Aidan in HCMC

CIA burners...

@OceanBeach92107

🤣

Hi everyone. I’ll be arriving in HCMC Jan 1. My plan is to explore SEAsia for a year, and stay indefinitely if I love it. I’ll have to new IPhones, one as a backup. I’ve done a ton of research but can’t seem to figure out what the best, cheapest way to use my phone will be. I have ATT service now. I want unlimited calls, text and data. I’m not a tech person, just want to use my phone as I do now and hopefully keep my phone # as I’ve had it for 30 years. Is what I’m looking for even possible in a cost effective way? And is there a way I can set it up so I won’t have to change things for each country I visit? Thanks so much, and I’m looking so forward to joining all of you there!!!

Different countries might well require different SIM cards in order to keep costs down.

There are cards like these

https://maya.net/plans/asia?gad_source= … W4QAvD_BwE

but I have no idea how good they are

Thanks Fred. Anyone else have any suggestions?

Thanks Fred. Anyone else have any suggestions? - @kevinodprobate

https://www.expat.com/forum/viewtopic.php?id=1078742

Well I "upgraded" from a iphone6 to a 12. 

I'm too absent-minded to invest big bucks in a newer model. I have my local plan on the e-sim and

will do a VN sim in the other. I'm not sure if it will allow me to use my US number through wifi, but because my old phone battery was dying, a new phone was needed.

If it were not for the battery issues, I would be quite happy with the Iphone6.  On a lark I bought a replacement battery on ebay for less than ten dollars, (includes tools)  it seems not to difficult to change, maybe in VN I will try it and keep it for a backup.

@Dannyroc3
Yes, if you get a phone that supports dual SIM cards, you can use one for your local NV number and keep the other for your US provider. This way, you can still receive important texts, like security codes, while using local service for calls and data. Just make sure your US service is set up to work internationally, and you should be able to manage both numbers easily. It’s a great way to keep your old number without losing access to your accounts! - @john hire

I think I mentioned before that I do exactly that using Globe postpaid for a physical sim and USA service Google Fi for an e-sim which does 2FA texted security codes, international SMS and 29 cents per minute international cell calling. Not sure if Google Fi gives free international Wi-Fi calling but that is a different subject.

Now, the one and only reason I do this is to have a "reliable", paid cell number to receive texted security codes for bank and credit card logins.

If the banks and cc companies were to join the modern world and allow authenticators and/or passcodes for 2FA, I would drop the Google Fi and save $24 per month.

From what I gather, people have checked and these countries are insisting on the SMS texting security code method for 2FA. They do not wish to go forward to more secure methods. This reluctsnce seems to have created a new scam called "SIM swapping". Basically the scammer phishes your personal information and convinces a non-expert call center employee for your ISP that you list your phone and wish to transfer your SIM to your new phone number. It has worked quite well as it seems to be easy to convince those call centers to swap the SIM. At that point the scammer receives your texts and drains you bank account. From what I can see, this is becoming a big problem and works on the principle of human call center employee naive and bank security ignorance.

Possible someday banks and cc's will begin to realize that the SMS text 2FA they are using is the least secure method available and then move into the more secure autheticator and passkey methods that do not require a real USA etc. cell number. However, I also suspect banks and cc's are willing to give up a little security because some customers may find that the use of authenticators and creation of passkey ID a little too complex for the average person. But note that the SSA website and your IRS account must be accessed at login.gov and id.me which use the more complicated but more secure authenticator 2FA methods.

@danfinn

Interesting. I've just got back to the UK from Jakarta yesterday and have had a notification from my UK mobile provider 'Three'. As part of the Apple IOS 18 updates (which I just updated to on my iphone 13) planned for week commencing 9 December text messaging for Three customers will be changing from SMS to a newer type of messaging service called 'Rich Communication Services' (RCS)

Apparently the new system will bring enhanced messaging features and will use data allowance not SMS allowance. You can though switch off RCS in phone settings if you prefer to use SMS. Its supposed to enhance messaging between Android & Apple devices and supposedly is more secure.

Would be interested to know if this is available elsewhere in the world.

@danfinn
Interesting. I've just got back to the UK from Jakarta yesterday and have had a notification from my UK mobile provider 'Three'. As part of the Apple IOS 18 updates (which I just updated to on my iphone 13) planned for week commencing 9 December text messaging for Three customers will be changing from SMS to a newer type of messaging service called 'Rich Communication Services' (RCS)
Apparently the new system will bring enhanced messaging features and will use data allowance not SMS allowance. You can though switch off RCS in phone settings if you prefer to use SMS. Its supposed to enhance messaging between Android & Apple devices and supposedly is more secure.
Would be interested to know if this is available elsewhere in the world. - @Lotus Eater

you are much more likely to get helpful replies if you create a new thread dealing with this specific subject.

My T-Mobile android phone from the USA continually tries to get me to make that change but I always decline, as it's really just unnecessary fluff and stuff

@OceanBeach92107

you are much more likely to get helpful replies if you create a new thread dealing with this specific subject.

Not sure about that. It relates to the topic at hand.

My T-Mobile android phone from the USA continually tries to get me to make that change but I always decline, as it's really just unnecessary fluff and stuff

One concern of many expats here has been the use by banks of SMS for OTP codes when trying to log on to online banking apps and cc's as well. Since  in the past, US cell phone numbers would not allow permanent roaming in the Philippines, this became a problem. No cell number to send the OTP code to. For many, google voice was a hack that worked and still does, for some Banks and cc's. MagiJack numbers do not work, as institutions discern MJ as not being in a cell network. It isvtotally voip which banks and cc's do not like to send codes to.

SMS vs ECS: SMS uses the cell phone networks, not data.

RCS, available in the US. uses data networks, not cell.

But banks always insisted on sending the codes to SMS over the cell network

So if you adopt RCS instead of SMS, how do you get your 2FA codes, to log on? Will banks now adopt RCS? (Probably not) That would be great but so far my institutions require you to have access to a cell phone with a US sim card.

T-mobile used to work here for that but stopped working in the Phils after 6 months.

Google Fi is a US number and US sim that will accept SMS messaging for USA 2FA OTP codes forever, apparently. Too many abbreviations I know.

In recent years there have been many reports of sim card swapping scams. In those cases, a hacker has your number transferred to the hacker's sim and, now receiving your sim SMS texts,  the OTP codes to log on are given to the hacker.

I wonder if my institutions recently became aware of this. It has been much rarer for them to request a text OTP to my (google fi) cell number. They do accept a fingerprint or face print in addition to password much more often now.

Is SMS 2FA going away, as it should, because it is less secure in thecera of sim swapping? That would be great news for many USA expats who struggle with a reliable 2FA OTP process in the Philippines.

If they do go away, then I can cancel my (reliable but a bit expensive) international google fi number for use in the Philippines.

I have suspected that banks and cc card companies will eventually move toward autheticators for 2FA. That would be highly secure. However, for many elderly expats, they may need to be sort of a geek to get authenticators working. I am not speaking about we internet experts on this thread lol.  Once you do get it established, it is an excellent method for 2FA...until you decide to get a new phone but that us a different subject.

This is the Vietnam forum.

People ask questions here to find out what works in Vietnam, not the Philippines.

This is the Vietnam forum.
People ask questions here to find out what works in Vietnam, not the Philippines. - @OceanBeach92107

Yes, I noticed that after I posted my information which is actually not specific to any particular country in Asia. So, OK  @OceanBeach92107 I have no idea how your Vietnam topic appeared on my expat Philippine forum feed. I was fooled because I saw a few other Phils forum regulars here as well but you chose to single out my comment to drop the hammer on me lol. No problem. It is too late to delete it so you will have to suffer my comment unless you can convince the admin to delete it. I will not comment further.

@danfinn

I was going to wait to post the end result of my dual sim card experience, as I have not gotten either a data sim or a phone number here in VN since I returned the otherday, but your post prompted me.

Since I have been here with my Iphone12  (newly purchased),  I have my US cell service on my e-sim and it still gets text messages through Wifi. I have not had a business send me a code to log it but I suppose it would work.

I did try to make a call back home through Wi-Fi but got a message in VN that I could not understand and have not tried again with help yet.

Didnt the dual sim card feature help or maybe you terminated your foreign phone service?

@Dannyroc3

Before my departure to asia in early November I loaded up the 'Airalo' esim to my iphone 13 (purchased in the UK so still has sim tray) . Like many of these new tech add ons the devil is in the detail. I found the process confusing and discovered that I would not be able to send text messages at least in Vietnam.

Oh sod it Lotus just grab a local sim at the airport and let the girls fit it and recalibrate my iphone accordingly. Job done.

The caveat being that I was not going to be in the country that long. If I was I might investigate the dual sim option further especially if I was an expat and needed a number for my home bank to contact me for whatever reason if only for a security check.