Cell Phones

Can I use an unlocked Canadian S9+ with all US carriers?

  • Last Updated:
  • Jan 3rd, 2019 8:28 pm
[OP]
Newbie
Mar 18, 2016
22 posts

Can I use an unlocked Canadian S9+ with all US carriers?

Hey,

I just got my S9+ the other day and am starting to learn about GSM and CDMA. Apparently Sprint and Verizon use CDMA while AT&T and TMobile use GSM. I also heard that GSM is now the global standard. So I am guessing that all Canadian networks use GSM? Also would my phone work with a Sprint or Verizon sim card?

Thanks!
24 replies
Deal Expert
Aug 2, 2004
32859 posts
6496 upvotes
East Gwillimbury
You’re partially correct

In the beginning there was TDMA and CDMA, then a small company called Microcell opened in Canada and started using GSM. Eventually the world caught up with technology and adopted GSM world wide. Rogers acquired Microcell to get a head start on GSM and eventually shut down their TDMA network.

GSM is basically 2G, it evolved to 3G and HSPA and then LTE

Most of the world is still on HSPA+ / GSM

Bell and Telus was on CDMA but eventually ditched their network in favor of HSPA / LTE. They don’t have a GSM network only Rogers and it will eventually be shut down.

In the US, AT&T and T-Mobile operate a GSM / LTE network. T-Mobile operates on the 1700 GHz band (Freedom). Sprint, Verizon still has an active CDMA network.

GSM is old technology, if you want to use your S9 in the US, AT&T is the best option.

FYI, Microcell = Fido
[OP]
Newbie
Mar 18, 2016
22 posts
Hey,

Got it thanks so much for the detailed reply! Very informative.

All the Best.
Deal Addict
Aug 18, 2018
1786 posts
1364 upvotes
Bay Area
@GuitarZan06

Sort of. Verizon and Sprint's CDMA network is 3G only, and their LTE network is fairly standardized like the rest of the world except they use slightly different bands. Your unlocked S9+ will work with Verizon, but most likely not with Sprint because they use an interesting IMEI whitelist system. Basically if you have an unlocked but non-Sprint branded phone, you need to get your IMEI whitelisted else you won't get any service. They're very specific about which phones they will and won't whitelist, and I highly doubt they'd do it for a Canadian "W" model. You're not losing out on much though since they're generally regarded as the weakest of the big four.
[OP]
Newbie
Mar 18, 2016
22 posts
Hey,

Thanks for the help. Yeah I heard Sprint was the worst as well in terms of US coverage. I am going to start with AT&T and see how that goes. With Red Pocket you can choose between any of the 4. So if I find that AT&T is lacking I can order a Verizon sim and try them for a mere $10.

All the Best.
Deal Addict
Aug 18, 2018
1786 posts
1364 upvotes
Bay Area
Sure Red Pocket is a reasonable choice to start. Just be aware they allow absolutely no roaming whatsoever (very few MVNOs do) if that's something that might be important to you. Where in the US will you mostly be using your S9+?
[OP]
Newbie
Mar 18, 2016
22 posts
In Washington state mainly. If I take a longer road trip I can add mins & data to my plan. Dumb question but how would no roaming affect me in the US. Does it have something to do with there not being any AT&T towers around (if I opt for AT&T) but I can't use another carriers tower in the area?

Thanks.
Deal Addict
Aug 18, 2018
1786 posts
1364 upvotes
Bay Area
Sorry I meant there's no international roaming. But yes you're also correct that Red Pocket offers no domestic roaming either. In Washington state coverage is about the same for AT&T, T-Mobile and Verizon in urban areas, but Verizon wins in rural areas.
[OP]
Newbie
Mar 18, 2016
22 posts
Hey,

After doing a bit of looking I think I will start with Verizon instead of AT&T. Have you heard of any negatives of Red Pocket? I was looking at Roam Mobility but heard their cell service can be very spotty. I looked at some reviews of Red Pocket and it looks like a very viable alternative, especially because they offer free international calling to Canada so I can call back home when I am in the U.S. as part of my minutes.

Thanks.
Deal Expert
User avatar
Jun 12, 2007
15647 posts
4717 upvotes
London
Gee wrote: ...In the US, AT&T and T-Mobile operate a GSM / LTE network. T-Mobile operates on the 1700 GHz band (Freedom). Sprint, Verizon still has an active CDMA network.
GSM is old technology, if you want to use your S9 in the US, AT&T is the best option...
Some minor stuff
GSM = only T-mobile and independents like Cellular One and only in legacy areas. Many new towers are LTE only

ATT shutdown their GSM network in 2016.

Verizon, ATT and TM offer " bring your own device".

Verizon BYOD requires a phone that they accept (VoLTE certified on Verizon networks)

ATT and TM offer LTE service on band 4 1700/2100. HSPA on ATT (850/1900) and TM 1900.

TM no longer offers HSPA on 1700/2100, Its all converted to LTE

There are many new TM rural areas where you must have a VoLTE phone on LTE band 12 (700 mhz)
Deal Addict
Aug 18, 2018
1786 posts
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Bay Area
GuitarZan06 wrote: Hey,

After doing a bit of looking I think I will start with Verizon instead of AT&T. Have you heard of any negatives of Red Pocket? I was looking at Roam Mobility but heard their cell service can be very spotty. I looked at some reviews of Red Pocket and it looks like a very viable alternative, especially because they offer free international calling to Canada so I can call back home when I am in the U.S. as part of my minutes.

Thanks.
The main negative with Red Pocket is the price. Because they give you a choice of all 4 carriers, they're more expensive than if you went with a carrier-specific MVNO. To get the lowest rates you have to pay a year in advance (highly not recommended unless you actually live and work in the US).

Roam Mobility operates a T-Mobile MVNO and has absolutely laughable rates by MVNO standards. Much better and cheaper options abound if you decide to go the MVNO route.

Honestly, I'd say figure out how many minutes, Canada calling, and data you'll need first, because each of the big three has different restrictions on their prepaid plans. Then when you throw their MVNOs into the mix, it becomes an impossible maze unless you know what you're looking for.
Deal Addict
Aug 18, 2018
1786 posts
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Bay Area
l69norm wrote: Some minor stuff
GSM = only T-mobile and independents like Cellular One and only in legacy areas. Many new towers are LTE only

ATT shutdown their GSM network in 2016.

Verizon, ATT and TM offer " bring your own device".

Verizon BYOD requires a phone that they accept (VoLTE certified on Verizon networks)

ATT and TM offer LTE service on band 4 1700/2100. HSPA on ATT (850/1900) and TM 1900.

TM no longer offers HSPA on 1700/2100, Its all converted to LTE

There are many new TM rural areas where you must have a VoLTE phone on LTE band 12 (700 mhz)
Good summary, and you reminded me of something I didn't realize earlier.

The S9+ Canadian W model has all the required bands and is 100% compatible with all the LTE bands from VZW, ATT and TMO. However, it does not have any of Verizon's 2G/3G CDMA bands, and will also not work with ATT 2G because it no longer exists. This means if you can't get an LTE connection on Verizon, you will not get service at all. ATT can still work with 3G, and TMO you can even limp along on 2G if it gets that bad.

The funny thing is the hardware is actually identical between all the S9+'s sold in US and Canada, it's the firmware that controls what bands the modem has access to. A more involved (but much more flexible) solution would be to flash the "factory unlocked" U1 firmware to the S9+ to unlock all the bands, and this makes it 100% compatible with all the US carriers. An added bonus is the U1 firmware never install any carrier bloat, and automatically configures the bands and aggregation depending on the SIM card you insert, all without the need to do a factory reset.
[OP]
Newbie
Mar 18, 2016
22 posts
Hey,

Haha so with that VOLTE deal would a S9 Plus still work on Verizon? Kinda confused. I would be interested in the MVNO route for sure. I am really only looking for something small. 100 mins, 100 texts and 500gb/month would be fine. Big thing though is being able to call back to Canada as part of those mins. I will continue looking.

Thanks!
Deal Addict
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Nov 14, 2003
4245 posts
2533 upvotes
Gotham
GuitarZan06 wrote: Hey,

Haha so with that VOLTE deal would a S9 Plus still work on Verizon? Kinda confused. I would be interested in the MVNO route for sure. I am really only looking for something small. 100 mins, 100 texts and 500gb/month would be fine. Big thing though is being able to call back to Canada as part of those mins. I will continue looking.

Thanks!
VoLTE is part of the carrier firmware so it generally only works with the carrier you purchased the phone from.

Have you considered a data plan and Google Voice? This is carrier independent and the GV number is yours forever.

I use a S9 (from UAE) with GV and a t-mobile data plan.
[OP]
Newbie
Mar 18, 2016
22 posts
Hey,

Ok that looks interesting. So I get a data plan in the states, and then put google voice on my phone and I can make domestic calls in the U.S. as well as call Canada from the U.S. and there is no charge other than the data I am using through my US provider? That seems like a cool option.

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