If you've ever gone to a foreign country with a carrier-branded phone, or tried to use that phone on a different operator in the US, you've probably encountered the problem many have: it's locked. While most carriers did honor unlock requests in the past, or sell their handsets unlocked (like Verizon, mostly), there was no universal policy on the practice in America. As of February 11th, that's changing - the CTIA (basically, the wireless industry's special interest group) is laying out a set of phone unlocking (that is, SIM/network unlocking) principles that AT&T, Verizon, T-Mobile, Sprint, and US Cellular will abide by in the wake of the congressional un-banning of phone unlocking.

If you're interested in phone unlocking itself, I've got information on that at the end of this article. This first part is just about what the CTIA's new policy will mean for the process of unlocking your phone in America.

The FCC has a good guide on the CTIA's changes right here, but I've tried to condense that down into a more digestible and practical format for you below.

What is the definition of "unlocked" here?

As far as I can tell, the CTIA means 100% real, actual SIM unlocking. Carriers like Sprint that historically had offered unlocking only for international travel (but still restricting domestic usage) now must fully unlock their devices for domestic use, as well. The exception is Sprint phones launched before February 11th - those devices can only be internationally unlocked, but will still have a domestic lock (eg, unable to be used on AT&T, T-Mobile, Verizon, or any other domestic network).

Where can I find individual carriers' unlocking polices?

Can I unlock my phone immediately on February 11th?

Only if the phone is paid off or your contract term is completed - and your account is in good standing. If you're currently on an installment plan to pay off your phone (Next, JUMP, Edge, Easy Pay), your carrier is not obligated to unlock the phone until all installments are paid in full. If you bought your phone on a subsidized 2-year service agreement, the carrier doesn't have to unlock it until that 2-year period is up or you terminate the contract and pay an ETF. Oh, and even if you are eligible, carriers have 48 hours to complete the request.

How do I know when I can unlock my phone?

The new policy requires carriers to provide you notice when the phone is eligible for unlocking, and do so in a "clear" way. Yes, that language is hazy, and some carriers are loathe to provide anyone obvious notice that they're no longer obligated to be their customer anymore. The other catch is that if you're a prepaid subscriber, the carrier only has to let you know when the phone can be unlocked at the time of sale, no future notices are required.

Can I somehow unlock my phone before it's eligible?

If you ask very nicely, it's always possible a carrier will give you the benefit of the doubt (especially if you're a multi-line or business subscriber). And even if they won't, there are services on the web offering paid unlocking services for most GSM (T-Mobile, AT&T) carrier-branded smartphones. Costs range anywhere from $10 up to $50+ depending on the phone, carrier, and how quickly you want the device unlocked (I won't recommend any, because there are so many out there). Unlocking services for Verizon or Sprint devices are harder to find and generally more expensive.

Will my phone unlock automatically when it becomes eligible?

Only Sprint has gone so far as to say they will automatically unlock phones after the contract or installment plan is fulfilled (fine print: phone must have been sold after February 2015). All other providers require you to submit a request. Again, most Verizon devices are SIM unlocked out of the box, but the few that aren't will require contacting Verizon. AT&T, T-Mobile, and US Cellular all require "requests" for unlocking, but T-Mobile ships an app on its newer phones specifically to unlock the device that should work at the time it becomes eligible, so it's only a "request" in the technical sense.

Can I be charged for unlocking a device?

Only if you are not currently a customer of the carrier which you are petitioning to unlock a phone. Then, the carrier may charge a "reasonable" (yay vagueness) fee to unlock the device. We don't have pricing for these services yet, and we don't know which carriers will charge for it. The good news is that the new rules require the carriers unlock eligible phones (not a bad IMEI, payments fulfilled) regardless of whether you are or were their customer, they just can charge you for the privilege.

What about prepaid customers?

All of the big four's prepaid brands are participating in this new policy. That means AT&T GoPhone, T-Mobile Prepaid, MetroPCS, Verizon Prepaid, Virgin Mobile, Boost Mobile, and Sprint Prepaid. However, the requirements for prepaid customers are different. Prepaid phones must be unlockable after 1 year from purchase (before that is fine, too), but carriers can add requirements that the phone has been used with a paid account during that time. The requirements need to be "reasonable," but that's about as clear as mud.

Which carrier has the best / most consumer-friendly unlocking policy?

Verizon, surprisingly. Almost all of Verizon's modern phones are sold SIM unlocked out of the box, and work with GSM carriers around the world, and even on AT&T and T-Mobile (though T-Mobile HSPA+ coverage may be poor).

Which carrier has the worst unlocking policy?

AT&T, unsurprisingly. AT&T requires consumers submit an online request to unlock a device, with their phone number, IMEI number, the account holder's first and last name, the last 4 of your SSN, your AT&T account password, email address, and - just to insult you a bit - a captcha.

If you have more questions, I'm happy to add them to this article and answer to the best of my abilities. As to the basics of device SIM unlocking and what it does and how it works, here are some primers.

Can I used an unlocked [X phone] on [Y network]?

Short answer: with 3G HSPA+, maybe! With LTE? Less likely. In regard to 3G connectivity, the answer is generally "yes" if you're bringing any other carrier's unlocked phone to AT&T or T-Mobile. Even Sprint phones sold today generally have full HSPA+ compatibility with AT&T and most of T-Mobile. If you're trying to bring an off-network phone to Sprint or Verizon, the answer is generally "no," unless you're talking about a Nexus 6 or an iPhone 6, though with Sprint the latter still won't work. In regards to LTE, there is extremely little cross-compatibility among the big four carriers in America. The only band I know of with compatible adoption is 1900MHz PCS (Band 2), which AT&T, T-Mobile, Sprint, and Verizon all use, but it's highly geographical and there's precious little overlap yet. T-Mobile and Verizon also share 1700f, aka Band 4, so there's overlap there, too. The other issue is that AT&T and T-Mobile phones still don't generally work on Sprint or Verizon (again, iPhone 6 and Nexus 6 aside), because Sprint and Verizon still require legacy CDMA support on their devices.

What phone is the best for moving between different carriers or around the world?

For domestic carrier switching, it's the Nexus 6, hands down. The Nexus 6 will work on all four major carriers' LTE and 3G networks right out of the box, something the iPhone 6 can't even do. Oddly, Sprint's iPhone 6 (once unlocked) is the best for international travel because it's the same model sold in Europe, and has tons of European, Asian, and Middle Eastern LTE support. Sprint's iPhone 6 doesn't work on AT&T, Verizon, or T-Mobile's LTE, though (it should work on ATT/T-Mo 3G, however), and the other thing to consider is that many foreign carriers don't offer prepaid LTE SIMs at this time, so you'd have to actually be a post-paid subscriber or roaming to take advantage of that band support. In reality, being an AT&T customer is the better bet if you want true international LTE - they have the roaming agreements, and no one else does at this point.

OK, what's the best Android phone for international travel?

Honestly, they're all pretty similar here. The first thing to know is that LTE roaming agreements between US and international carriers are basically nonexistent right now unless you're talking about AT&T, who has over 200 such agreements (T-Mobile, Verizon, and Sprint, as far as I can tell, have a grand total of zero). However, almost any Android phone you buy today has the standard GSM HSPA+ compatibility that includes the world's most popular set of frequencies. If you're truly concerned with the greatest amount of international coverage possible, the phone isn't as relevant as the carrier, as AT&T currently provides the most comprehensive global LTE roaming capability. The Nexus 6 has probably the most bands of any Android phone sold in the US, so it's technically the winner here, I'd say.

And that's the skinny on unlocking - like I said, if you have more questions, ask! The new unlocking rules, again, go into effect on February 11th, 2015.