This guide explains how to tell if your GSM (SIM card based) cell phone is unlocked, the benefits of an unlocked cell phone, and how to unlock your cell phone if it is not yet unlocked. Basically, once you unlock your GSM cell phone you can use it with many different carriers' SIM cards, not just the one you originally purchased it for. You will never have to rent a phone again every time you travel to a different country because 1 unlocked GSM Quad-Band phone will work anywhere in the world with ALL GSM carriers!

No matter how many lies your cell phone sales rep tells you, YOU REALLY CAN USE YOUR GSM PHONE WITH ALL OTHER GSM CARRIERS IN THE WORLD!

First, let me explain the difference between GSM phones and why some won't work in other countries:

There are 4 different frequencies of GSM service around the world: 850MHz, 900MHz, 1800MHz, and 1900MHz. Most cheap phones are single or dual band, meaning they only work on 1 or 2 of those frequencies so they will only work in the region or country you bought it. Most high-end phones are Quad-Band meaning they work on ALL 4 frequencies. You want to unlock a Quad-Band phone because that will work with ALL carriers and in ALL countries around the world!

What is a locked cell phone? Why is it locked? Can I unlock it?

The definition of a locked cell phone is a cell phone that is programmed to only work with 1 GSM carrier. Almost all wireless carriers such as Cingular, T-Mobile, VoiceSteam, etc started a marketing ploy a few years ago of enticing customers to buy their service by paying for most, or all, of the cost of a new cell phone (instead of the customer having to buy it) if the customer would commit to a one or two year contract to use their wireless service. That's why so many companies offer you a FREE PHONE if you sign up with them for a contract!  The wireless carriers did not want that expensive phone to be able to be used for free at a later time by the customer with a different carrier, so they got the cell phone manufactures to program the phones to be locked so they only work with their service and no one else's. For example, if Cingular paid for your FREE PHONE when you activated service with them, Cingular locks it so it could only be used on Cingular, with only a Cingular SIM card, and not another carrier's SIM card (like one from T-Mobile).  This lock has several common names including: "SIM Lock", "Restriction Code", "Sub Lock", or "SPC Lock". Sure, a T-Mobile SIM card fits into your locked Cingular phone because ALL SIM cards in the world are the same size, but it won't work in a locked phone due to this lock code programming. The good news is you can unlock ANY GSM phone. Most are easy to unlock just by typing in a code, and some others (like PDAs) just take a few extra button presses.

Now you know why 95% of all carriers lock their phones, so this is how you can tell if your cell phone is locked:

If you put any other carrier's SIM card in the phone it will not turn on, you will just see it asking for a code such as: "Subsidy Unlock Code", "Enter SIM Unlock Code", "Enter SPC Lock Code", "Restriction Code", etc. If you bought it in the U.S. directly from a provider's store (Cingular, T-Mobile, etc) then it is locked for sure because all U.S. companies lock their GSM phones. If you bought it in the U.S. from a reseller like those little "mom-and-pop" shops that sell a bunch of different carriers then they are usually locked, but not always.

How can I unlock my cell phone?

You can find hundreds of companies that unlock cell phones on eBay and on the internet. The local "mom-and-pop" shops can usually unlock most phones, but charge you way more than the internet companies will. Most internet based companies are able to unlock most phones remotely. All you have to do is send them the IMEI serial number on back of your phone (all phones have one, it's right above the bar codes) and they will send you a code to unlock the cell phone.Some companies ask you to send them your phone. Each model is different, so you will have to search a little to find the best deal for someone to unlock your particular phone model. These unlock codes are usually $4.00 to over $100.00 depending on the model of the phone you have and which company you choose to buy the unlock code from. In general, the more expensive or unique your phone is (like an iPod Touch or other PDA, all-in-one, smart phone) the more expensive the unlock code will cost. A local shop near me was charging $120 to unlock PDAs, $80 to unlock a Motorola RAZR, and $60 to unlock common Nokias. I found unlock codes for them on the internet in 10 minutes for $40 for the PDA, $25 for the RAZR, and $4.25 for the Nokia! The steps were easy too, I just had to put in a different SIM card so it would ask for the code and I typed in the code I just purchased! That was it!

Is there any reason I should not try to unlock my own cell phone?

No. The only thing you have to be careful about is typing in a wrong code too many times. All SIM locked phones only allow 5 tries total. The 5th wrong try locks the phone completely so it won't turn on or work at all, and you have to send it back to the factory to have them reset it which takes a few weeks. So as long as you have the right code, there will be no problem!

If you are unfamiliar with the process and are afraid you might make a mistake unlocking it yourself, just buy one that is already unlocked from eBay or one of the many local independent resellers in your town like "Cellular Bargains" or "Cellular 2000" in your local mall. Keep in mind that any unlocked phone from eBay will probably be half the cost of buying it from any local shop because local shops love to overcharge you!

So to recap:

Buy a Quad-Band GSM phone (works on all 4 GSM frequencies)

Unlock it by finding a company online to sell you a cheap unlock code, or buy a phone that is already unlocked from eBay.

Use it with any carrier's SIM card in the world, anywhere you go in the world! No more having to rent those expensive travel phones, or buying those expensive prepaid phones or cards in every country you travel to!

Unlocked phones also have a higher resale value because you can sell them to ANYONE in the world, not just people on 1 carrier!