Some cell phones are designed to use a Subscriber Identification Module (SIM) card, or microchip that stores subscriber data. The SIM card is issued by a carrier and provides cell service by activating any phone into which it is inserted. A locked phone, however, will only recognize a SIM card from a particular carrier. If the cell phone is unlocked, it will recognize a SIM card from any carrier. The "lock" is a software setting that keeps the cell phone "loyal" to one carrier.
In areas like the United States where carriers offer free or deeply discounted phones with cell plans, the phones are commonly locked so that they will not work with other carriers. Carriers claim this is necessary to subsidize the cost of the phones. After a period of time, a carrier might agree to unlock the phone upon request, perhaps charging a fee. However, due to proprietary settings sometimes installed in locked handsets, the phones don't always function correctly with other carriers, even once unlocked.
From the viewpoint of the consumer, the practice of carriers locking phones and using proprietary settings defeats many of the benefits of SIM handsets. Complaints led to a class action suit filed in California in June 2004 by American watchdog group Foundation for Taxpayer and Consumer Rights (FTCR). Ideally phones should be left unlocked, or at least unlocked after the initial contract expires.
One way to get an unlocked phone without proprietary settings is to buy it new from a third party vendor in its original, unlocked state. The downside is that the price is commonly close to full retail. Some consumers might find it tough to dish out big bucks for a phone that they can get for free with a plan. The advantage is that the third party unlocked phone should work equally well with any carrier that uses SIM cards.
Unlocked cell phones are in such demand that third party services will unlock your cell phone for a fee. This doesn't guarantee the phone will always work correctly, as proprietary settings might remain. There are also hacking instructions online to unlock many models of phones, but a phone that is unlocked improperly can be rendered inoperable.
Carriers operating on the GSM network use SIM cards. In the United Sates, this includes Cingular Wireless, now one with AT&T Wireless, and T-Mobile. Carriers that use the competing CDMA network do not yet use card-enabled phones. These carriers include Sprint PCS, Verizon and Virgin Mobile. The CDMA equivalent of the SIM card — the R-UIM — will be used by these carriers in the future. R-UIM cards are already in use in some parts of Asia.
i bought an unlocked blackberry 8520 yesterday. It's working fine. I love this phone. Now white color is also out. May be will buy white color soon. thanks, mandy
- anon51416
137
can you unlock iphones for tmobile?
- anon51389
136
Ouch! Too much confusing info. Not enough answers. Is there a central, perhaps federal agency that has all the answers?
- anon48115
135
i just purchased a new iphone and want to unlock it and then put in a new sim card that is good all over asia, india, thailand, singapore, hong kong, china, okinawa and taipei. Is there any one plan that i can use to both unlock it and purchase minutes? I want a plan that does not charge for incoming calls and will give an 880 number in the us if my children want to call me. thanks.
- anon47913
134
Can I use an unlocked Iphone with virgin mobile prepaid service?
- anon47587
133
this article is nice. thanks.
- anon47526
131
I'm using Sprint now, and I really want to change it to another phone. Actually, I got a this phone which is "unlocked" Nokia 6288. I don't know how to activate this phone. I mean, should I bring it to any cell phone shops? and then what? Buy a GSM card? or what should I do to use with this phone?
- anon47428
130
I am thinking about buying the Blackberry tour (the newest phone from Verizon that comes with a SIM card and can be unlocked) because I am in and out of the country every few months. I have a blackberry already and am paying a butt load for my plan, as well as having a phone in this other country that is a prepaid. I was wondering if anyone knew if I switched my card from my prepaid and put it into my new Blackberry, would I still have to pay for my plan at home in the states on top of adding money to my phone while in this other country?
- anon47263
129
can I use a nokia 5530 on the net10 network? Thanks.
- anon46696
127
I have spent a lot of time researching and looking at purchasing unlocked phones. I decided to make my purchase with JAB Cellular and I am so glad I did! These folks were awesome! They had outstanding pricing, amazing customer service, and my order arrived the next day for only $9.95 for shipping charges. It doesn't get much better than that! They have a very large inventory, and can pretty much special order any phone, should it not be in their catalog already.
- anon45948
126
There are a ton of questions here which basically all ask the same thing. How can I save money and have the most flexibility? The answer has two components: get a phone that has a SIM card, and *ensure* that it also supports at a minimum tri-band frequencies. Quad-band frequencies are better since they are supported worldwide. You'll never find anything in North America lower than dual band since North America itself uses two frequencies.
Once your phone is unlocked you simply pop out the SIM card and replace with another SIM card (this SIM card can be a card from another country if you want).
If you go to, for example, the UK, you simply purchase a new SIM card (for 5 or 10 pounds) from a carrier over there (O2, or Virgin, etc.) Pop it into your phone. If your phone is a tri-band or quad-band model, then you are all of a sudden a local phone in the UK and will pay local rates for calls to the UK. You will pay International rates to call home. If you leave your home SIM card (North American) in the phone you will roam. Each time you make a call to a UK number, you will pay a roaming charge plus a specific local rate (likely to be more than if you used the local UK SIM card). If you call home, you will pay International rates.
The moral? You will *always* pay international rates when making international calls. The difference comes in using a SIM card to change what is considered your local location.
- anon45881
125
i have a questionm. as of right now i have the att network, i wanted the blackberry but didn't want to pay the 30 unlimited data fee that was required with getting this phone. If i get a unlocked blackberry willl i still need to pay that fee even if i do not use email or go onto the internet with the phone?
- anon45779
124
hello, i found there are many unlocked phones online. are those true? who can tell me. thanks!
- anon45123
123
Ok, here is what I know and I hope it helps some folks.
I purchased an unlocked blackberry while I was in another country, it cost me right around $400. I have had no issues with the phone (but from what I have been reading if you get your phone unlocked as opposed to purchasing one that was never locked is sounds like they can be pretty buggy due to some software issues.) I have a few different SIM chips that I use with my phone, one is a plan that I pay monthly (for the States), the others are all foreign Pay as you Go chips with foreign carriers. if your service provider in the States does not operate in a foreign country you have to purchase a different chip for your phone. A note on this, if you are using a foreign chip it is like you are a ‘local’, you can call back to the States (and people from the states can call you) but it gets expensive fast because it is an international call. All my SIM chips have different phone numbers. Before you purchase a phone I would make sure that it is SIM compatible. There are some services that don’t use SIM chips (AT&T, T-Moblie, Verizon, Sprint, Alltell) so you cannot use these service providers, as their chip will not fit into your phone, any phone that these companies produce you will not be able to use a SIM chip in.
- anon43525
122
I have a canadian IPhone 3G and my american AT&T sim card is not finding any service when i use my IPhone with it. Why does this happen?
- anon43033
121
I plan to visit Italy. I understand that I can buy an unlocked phone there and a pay as you go SIM card and call anywhere in the world. Is that correct? When I buy an unlocked cell phone, where do I get the phone number for the unlocked cell phone? Can somebody help?
- anon42606
120
There's 100 questions here and only a couple of answers. After reading all the questions, i'm really confused.
Buying an unlocked phone: Will that allow you to use all its features (internet, e-mail, etc) without subscribing to the additional services?
- anon42480
119
Wow, I really can't believe some of the questions here. The best thing if you are planning on buying an unlocked phone, is to check with the carrier you are with or planning on going to. If the carrier supports the "frequency band" of the phone, put in the SIM card and there you go. If the band isn't supported, look for a different phone. Unlocked cell phones are 100 percent legal in every country. So let's sum up: if you want to use an unlocked phone, check with the cell provider, they will be able to tell you. Other things to remember, Verizon, Alltel, and some others do not use sim cards. if looking to buy an unlocked phone for use with any company that doesn't use SIM, do not buy a SIM phone!
People, please do your research.
- anon42441
118
I have a verizon cell phone and some of the features are not working. If I bought a unlocked phone, would I be able to transfer it to my carrier?
- joeycerra
117
If I buy a smartphone and have at&t service do I have to get their data service to access the internet, or does their data service just allow me to connect through their hotspots?
- anon41649
116
I saw a blackberry phone on eBay which is unlocked in the UK. If I buy this phone, can I use a prepaid SIM in the phone? Thanks!
- anon41324
115
I am will be spending the winter months in Panama and would like an unlocked phone that I can use there as well as the USA. Any suggestions?
- anon40514
114
How do i know my Blackberry 8100 Pearl handset is locked or unlocked?
- anon40500
113
Yes unlocked phones are legal. In fact most cell phones in Europe are unlocked as most people use pay as you go and change out their SIM card whenever they go to a different country, and there are phones, such as the iPhone that are free on contract over there. SIM cards are the same size, so it will work in any phone. You can't use a G1 with Sprint because Sprint does not use SIM cards. GSM networks (AT&T, T-Moblie are GSM) Verizon, Sprint, Alltell use CDMA which do not use SIM cards.
- anon40426
112
I want to get the T-Mobile G1 phone, but want to get Sprint service. Can I make this work by getting a G1 that's unlocked?
- anon39868
110
I just purchased an iphone from ebay. it's unlocked and ready to use. just put in the sim card. first, is the phone working under the plan that the person I purchase the phone from has? can someone explain to me how all of this works? Thanks
- anon39598
109
if i have a boost phone and put my sim card in it will i keep my number if i go to the boost site and update phone
- anon39435
108
if i have u.s cellular and want to get an iphone is it possible to use an unlocked one?
if not which phones can i use that u.s. cellular doesn't offer? thanks
- anon38763
107
I have T-Mobile service, but will change to Cricket here soon, so after unlocked my bb pearl, can someone tell me what to do next, do I just simply enter some kind of code from my new cricket phone? if any one can help me, I would much apreciate it. Thanks
- anon38327
106
Unlocked cell phones should be able to use and compatible to any cell phone providers out there.
- gengin
104
Do unlocked cell phones work for prepaid wireless service?
- anon37459
103
Hi there,
I have the same questions as Bob #93. I live in Ontario and wonder if any of the unlocked phones I buy on ebay will be operational in Canada. Thanks!
- anon37345
102
So can I just buy a plan from a carrier and use it for my phone? how does that work? I want to buy a samsung omnia or a blackberry bold but don't want to pay samsungs fees. how will I get a plan from a different carrier to work with an unlocked phone?
- anon37277
101
It is a good idea to purchase an unlocked iPhone 3g for use in China?
- anon37087
100
Are all sim cards the same size- they will fit in any phone?? I have a Tmobile network and want to get an unlocked iphone- should be fine right???
- anon36461
99
can you use an unlocked phone as prepaid and does it cost extra??
- anon36316
98
the sim card inserted in this iphone does not appear to be supported
what will i do
- anon36280
97
If I purchase a net 10 prepaid phone that has it's own SIM card, would that sim card work in an unlocked phone?
- anon35932
96
are unlocked mobile phones legal in any country?
- anon33538
95
So you cannot use other unlocked phones on verizon wireless?
- anon32959
94
i have net 10 prepaid. will my sim card work in an unlocked phone? i don't like their phones. -bill
- billhowell
93
I live in Canada (Ontario) but I'd like to buy an "unlocked" cellphone in the US (on ebay). If I do this and buy a SI card from a Canadian service and a monthly card from them, can I use it in Canada?
Bob
- bobdut
92
can i use a prepaid sim card from a T-mobile phone in an unlocked phone by just installing it and will it fit as some appear to be different sizes?
- anon32105
91
I am using a Nokia 2365i mobile & I got the unlock instructions as well as unlock code online. Shall I use another network in this model & resell it?
- anu
90
I am *totally* new at this so bear w/me, folks. First, if I buy an unlocked cell I should (or definitely will) be able to use it w/my SIM card in it? Or is this just a crap shoot? I'm a T*Mobile user and feel that I am in trouble since my cell died on me and my insurance was for only one year from when I purchased it. I can't afford to buy a new phone -- gotta wait until November (which is what the T*Mobile reps told me) whereby I can get a decent deal on a cell OR wait until it's time to renew my contract (which is in January) and get a better deal on a new cell. I need something now. Help!
- yallen
89
Will an unlocked phone be able to work on the Sprint Network?
- Diablosniper
88
I have net 10, but do not like their phones. Can I
buy an unlocked phone and use my net 10 sim card in it?
- bjg
86
If I buy an unlocked cell phone and take it to say my local Alltel provider would I be eligible for any different rates than I would getting my phone through Alltel? My second question is If I were to buy a Blackberry or Iphone and buy a Boost Mobile SIM card to put in them can I use the $50 a month unlimited plan with those phones?
I guess I am just unclear as to why I would want an unlocked phone other than using it to travel or using a phone not carried by your provider?
- shelli555
85
I want to know if a newcomer can use an unlocked cell phone? So then what do I need to buy besides an unlocked cell phone? A subscription plan, pay as you go, or a SIM card?
- anon31162
84
Are there unlocked phones that can be used with sprint as the provider?
- jay67
83
Would An Unlocked Hello Kitty Gsm Phone work in the United States?
- anon30361
82
I already have a verizon phone, but I like this at&t phone. Can I use the at&t phone on my verizon service?
- anon29804
81
I have 9 months left on my t-mobile contract and I'm content with their service. The problem is I want a phone that another carrier has that is not offered by t-mobile. Can I use my sim card with their phone if I purchase an unlocked phone of that type and still have the same service and regular cell phone functions that I have now.
- lionheart
80
I have an unlocked at&t tilt aka kaiser Htc tynn. My question concerns how do I get T-mobile software on and At&t software off?
I am trying to sell this phone and it's confusing to potential buyers. From T-mobile when they place their sims in and it still shows at&t software it is unlocked because otherwise it would ask for PUK a code or message insert sim card.
I unlocked it myself when contract was up requested and received the PUK code used old t-mobile sim card. Any information would be appreciated. Thanks
- shiloh64
78
Once a cell phone is unlocked would I still have to pay for extras like GPS and Web access? Or is all this unlocked to me? If not, how can I get all this for a low cost?
- open1
77
If I bought an unlocked phone intending to use it with Metro PCS, would all the features that metro supports work, or just some?
- jillactor
76
I was thinking about buying a unlocked phone, but i do not know if it will work with US Cellular? If any one could answer my question that would be great.
- pirate73
75
So if I by an unlocked phone (considering the an unlocked model of my current phone)will I need any special code, etc. to enable the internet browsers, email connections,etc.? All I have to do in put in my sim card & go?
- anon25788
74
I bought a Motorola trac phone and i like the size. Can i activate this phone on my Verizon account?
- loonster5234
72
Do i have to pay for service with the sim card? I have verizon but want an i-phone and i can't afford the switch to another carrier.
- anon25535
70
i want to buy a unlock phone from t-moble but i have at&t and i am wondering will the phone work when i get it for at&t
- taytay10
69
so, will an unlocked phone work with a Net10 or TracFone SIM card?
- cncisco
68
hey, for all you guys that are asking if the unlocked phone will work with your SIM card, look up the phone you want on ebay (there are tons of unlocked phones there) and read the description. it should tell you which SIM cards it works with and answer any other questions you have.
- anon23853
67
I want to buy a phone from ebay.online auction....will it work in India?
- anon23491
66
I plan on buying a phone as a gift and I know my friend uses ATT and still has a year under the existing contract. I was wondering what my safest bet was? I would hate to get a phone that couldn't be used!
- anon23395
65
Could you use an unlocked phone with Tracfone?
- anon23316
64
If I buy an unlocked cell phone, and transfer my sim card from my old AT&T Pay as You Go Phone, is it necessary then to go to AT&T Dealer if I want to retain my current number????
- anon23252
63
good web page... I am a tech nerd and I still did not know what it means to have an unlocked phone... keep seeing all these ads for "unlocked" phones, I wanted to know... now i know and knowing is half the battle... GO Joe.
- anon23017
62
thank you soooo much for this... i didnt quite understand the concept but now i do...i have a question though... if unlocked means they can read any sim card that's inserted in the phone... does it mean that i can insert sim cards from any country; because i live in panama, latin america and i travel to the U.S and a lot and i was wondering if i could just buy one of these phones and buy a sim card of an american carrier and use it when i'm there and when i get back use my regular sim card??
- mariz0107
61
Thank you sooooo much!!! You are providing such a great service for all of us non-geeks. Thank you Thank you Thank you!!!
- anon22875
60
I am trying to get the sim card out of a Samsung SCH-U340 ... pretend you are speaking to a child and explain how to get to the card ... is it under the battery, do you have to unscrew the phone to get to it? Thanks!
- anon22331
59
This article is very helpful. I am just looking into the concept of unlocked cell phones. I am learning about SIM cards and the different networks GSM and CDMA. There is one thing I do not understand. If I purchase the unlocked cell phone I want and insert the SIM card, am I good to go? Do I have to sign with or notify any company? Is there a next step I am missing? Thanks so much.
- MoselyJ3
58
im lookin to by a unlocked iphone that works with a Sim. i have verizon service. i was wondering if it would work with my service since verizon phones dont have Sim card in them
- mrhappy
57
I never knew what an unlocked phone was and didnt know about this site earlier but my answers were answered when i called popular electronics and bought a phone from them for a great deal! This site is very helpful as well thank You!
- nick0608
56
has anyone bought a phone from big time wireless?
Prices are good, but I never bought a phone online before.
Please advise. Thank you!
- ssa727
55
Cellhut is a great place to buy unlocked cell phone. They've got some cool next-gen phones from HTC and Nokia
- anon19595
54
I just purchased an unlocked LG Shine. My contract with T-Mobile expires in December. Then what? Do I pay for each call? Do I just continue to use the SIM card that I have from my T-Mobile contract? How will I be charged for calls / service?
- rmtar
53
I have a tmobile service and I am trying to buy a side kick slide and the phone is new and not unlocked will I have a problem with. Can I just put the sm card with no problem.
- pricanbeauty
52
Unlocked phones are awesome! they let you switch between sim card from different networks. I always use an unlocked phone because I travel a lot and it saves me a heck of a lot of money on roaming charges, i just buy a pay as you go sim card from my destination, pop it into the phone and it works straight away! Trust me you should use an unlocked phone, it's well worth it!
- anon17316
50
Can you use unlocked phones on U.S. Cellular?
- anon17007
49
I just bought an AT&T Tilt (8925) and bought an unlock code on the internet. Now I'm using my tilt with Fido in Vancouver on Pay as you go. so yes it works right away, just pop in a sim card and your ready to go! It's just great to have an unlocked phone, I'm planning on taking it to Germany with me in September and just buying a local sim card there. that way I avoid huge roaming charges.
- anon16897
47
If I want to purchase a cellphone online (a razor v3) that would work the "Cellular South" Network. A CDMA? What do I look for? Most unlocked phones say they are GSM or they are for Version/Alltel/US Cellular/etc.
- cmw
46
Warmbrown - You asked whether unlocking a phone is illegal? If the carrier will eventually do it for a fee what do you think?
- anon16339
45
does the SIM card of the Samsung ACE or the Blackberry 8830 World Edition from Sprint work with any unlock phone?
- rob007ny
44
how do I know if my phone is unlocked?
- anon14984
43
All 'unlocked' phones do is allow you to use the particular phone with any of the service providers that use SIM cards. There's no point in specifically buying one if you don't plan on changing providers or if your provider doesn't use SIM cards.
- anon13900
42
I am thinking of buying an unlocked phone. Will I be able to use it with a prepaid "jump" account. Jump is a division of Cricket? Thank you! Lin
- anon13582
41
I purchased a unlocked nokia 7360 from ebay and used my sims card from previous phone. I can't get a signal for the phone the carrier is AT&T do I need to contact them?
- taurus
40
I don't know if is legal to use unlocked phones or it could conceal a crime?
- anon12692
39
I bought a new phone from Palm as "unlocked". Turns out, it can only be used with AT&T. Isn't that a locked phone?
- anon12249
38
yes the iPhone can be unlocked. Most unlocked GSM phones will work on any GSM network.
- unlocked
37
If I buy an unlocked phone will it work with Suncom Wireless which is in Puerto Rico?
- lgrivera
36
can i unlock nokia 6101?
- anon9435
34
Can the iPhone be made unlocked? How, who would do it? Thanks, AlexK
- anon9099
33
I would like to buy a pda phone that can support any gsm network from 900/1800/1900, but i have the 3g sim card and it says that it covers 850/1900 network. The guy on ebay says that the phone will work with any of those 3 gsm (900/1800/1900). My question is, will the phone work if i insert my sim card even though it's a 850 network sim card?
- anon9036
32
I just purchased an unlocked blackberry 8310 to replace my 1st gen bb. When I insert the SIM card, will it use the phone number from the previous phone? Will I still have all of the same email server and bluetooth settings?
- anon8439
30
Does the nokia N95 work with cellular south?
- miket601
29
i just bought a nokia N95 on ebay. I have service with cellular south. they say i can't activate a phone unless i bought it from them. They don't use sim cards and don't carry that phone. The nokia N95 that I purchased is unlocked. Is there any way I can use the nokia N95 with cellular south?
- anon7665
28
I have a two year old Palm Treo 750. I wanted to switch carriers from Sprint to Verizon when I came up against the 'proprietary' aspect of the phone.
Being 77 and recently retired, am I forced to stay with Sprint, or is there a way for a wise geek to unlock this (now $400) pink elephant to use with Verizon?
- Brundin
27
i bought a unlocked Motorola Razr V3 on ebay and i have a nokia 90.
i have a <> card in my nokia....
can i put the card in the razr and it will work?
- anon7530
26
if you buy an unlocked phone off ebay, say the samsung trace, can you then use it as a prepaid phone?
- anon5805
25
No, you can't just put any old SIM card in a cell phone and expect it to work. If the card is not associated with an account at a service provider, you won't get any service (except maybe 911).
And yes, this article has nothing to do (currently) with Sprint. Sprint is not GSM, does not use SIM cards, and thus "an unlocked phone" is not a concept that applies.
- anon5460
22
Do you have to have a service plan or do you just put in a SIM card and then you can call anybody anytime for free? thanks
- anon4522
21
Is unlocking a phone illegal?
- warmbrown
20
Can the Nokia N75 be unlocked to use with T-mobile? I really like the phone,but I don't think T-mobile sells it. I want to be added to my husband's t-mobile acct and I like that particular phone
- warmbrown
19
I want to get the Unlocked LG enV VX990 that's meant to be for verizon but I have cinglular? Will it work?
- anon4463
18
i currently have sprint for my cell phone provider, i was interested in buying an unlocked cell phone but dont know a lot about it.... is it possible to use an unlocked cell phone with sprint?
- khensley
17
It is very VERY important you look at your sim card... for instance att in the us is running the 3g sim card. if you buy an unlocked super phone off the net that is for 2g sim card then you will most likely have issues when getting it on the us network. 2g and 2.5g sim cards are used everywhere else in the world as the networks are slowly changing over to 3g.
sim cards are in gsm network phones..
good luck..
- anon3548
16
Hi, I want an unlocked CDMA cello phone that I can use in Korea, where can I buy one. (they don't seem to have them here, or their $300.00)
- bluedragon
14
Can you use an unlocked phone with alltel?
- anon3141
13
According my experience, if the phone is unlocked, it will be compatible with any carrier's network with the same band that your phone supports, for example, if your unlocked cell phone supports GSM 1900,it can be useful in any network with GSM 1900 band.
In conclusion,you need pay attention to two factors: unlocked and GSM band.
I bought an unlocked cell phone on line days ago, which support four band, which means it can use in almost every countries on earth, and feel good, further more, it is inexpensive.
By the way, the online shop i dealt with is Uxcell ,you can get this shop with searchaing "uxcell" in goggle, and the phone i bought is :
"Nautilus" 3 inch TFT Touch Screen PDA 2.0 Mega Camera MP4 MP3 Mobile phone.
- reeliao
12
Is there anyway you can 'relock' a phone once it has been unlocked? I have an unlocked RZR and I'd really like to lock it back to the original t-mobile service.
- anon2357
11
Will an Unlocked cell phone work for U.S. Cellular??
- spoiledm91
10
From what I'm getting, if you use Verizon, Sprint or Virgin Mobile you cannot use an unlocked phone.
- anon2002
8
if i purchase an unlocked phone online is there any posibilities than it will work in my cellularone network?
- anon1841
7
I am a Sprint Cell Phone subscriber. My puppy has chewed my phone almost to oblivion. Is there any compatible phone I can use in it's place? I don't want to sign up for additional service time.
From what I have read, I don't think I can because of my service provider.
- marilone
6
If i purchase an unlocked cell phone from the states can I put my sim card from canada in it and will it work in canada???
- anon985
3
If I purchase a unlocked cell phone will I be able to use it on the Verizon network.
- sombra
1
Hello, I am planing on buying an unlocked cell phone (sony ericsson z610i) and it is NOT quadband. It only supports Tri Band 900/1800/1900. Is there a way to figure out if the Cingular plan that I am using right now can support any of the 3 mentioned above?