Apple now sells unlocked GSM iPhone 4 in America, but AT&T and Verizon still don’t offer authorized unlocking for a fee to existing subscribers.

This article has been updated with comments from Verizon and AT&T at the bottom.

Yesterday Apple began selling unlocked GSM iPhone 4 in the US. Lacking carrier subsidies, prices are $649 for the 16GB model and a hundred more for its 32GB counterpart. Unlocked iPhones arrive without a micro-SIM card so you can use them with any supported GSM carrier worldwide and without pledging to a lengthy service contract.

It’s a life-saver when travelling abroad because you can simply pop in a local carrier’s micro-SIM to temporarily use your iPhone on their network. America isn’t the only country where unlocked iPhones are being offered. Per this support document highlighting iPhone carriers around the world, some or all carriers or authorized Apple distributors in each of the following 34 markets offer contract-free iPhones:

Belgium, Czech Republic, Finland, Germany, Greece, Italy, Luxembourg, Netherlands, Romania, Russia, Slovakia, Turkey, China, Hong Kong, India, Indonesia, South Korea, Macau, Malaysia, New Zealand, Singapore, Taiwan, Thailand, Vietnam, Brazil, Colombia, Ecuador, Mexico, Bahrain, Kuwait, Qatar, Saudi Arabia, United Arab Emirates and South Africa. The list lacks US because only Apple, not carriers  nor local retailers, offers contract-free iPhone in its 200+ retail stores across the country. In many other markets carriers are required by law to offer contract-free phones alongside their subsidized counterparts, with sales usually restricted to carriers’ online stores.

More importantly, even though many international carriers offer authorized unlocking, that’s still not the case with AT&T and Verizon in the US. Authorized unlocking refers to a simple technical process that removes carrier lock the official way, allowing your iPhone to be used with any supported GSM carrier worldwide. The service mostly entails an additional fee that covers the remainder of your carrier subsidy. It appears AT&T has no immediate plans to offer authorized unlocking to existing iPhone 4 subscribers. Twitter user Chronic contacted AT&T to no avail:

This doesn’t mean AT&T or Verizon won’t offer the service in the foreseeable future, even if it would be a first for an iPhone carrier in America. Neither carrier would loose subscribers to each other because their networks operate on incompatible radio technologies (GSM for AT&T, CDMA for Verizon). As a result, an officially unlocked AT&T iPhone cannot be taken to the Verizon network and vice versa.

True, some churn might occur with a portion of Verizon users taking their iPhones to CDMA-compatible Sprint (or to GSM-friendly  T-Mobile USA in AT&T’s case), but customer satisfaction gains would offset any short-term revenue loss, in my personal opinion. I don’t think anyone benefits from this situation where if you visit another country, you must cripple your phone by disabling cellular data in Settings in order to avoid exorbitant roaming charges. Make sense?

[UPDATE 1, June 15, 2011 1:25pm Eastern time]: A Verizon Wireless spokesperson has replied to our email inquiry, providing the following comment:

Per this comment, you should be able to take your Verizon iPhone to any carrier whose network uses the same CDMA radio technology as Verizon’s. If it’s any help, IntoMobile.com has a useful article on some Cricket Wireless stores flashing CDMA iPhone 4 to work on their network.

[UPDATE 2, June 15, 2011 5:13pm Eastern time]: A company spokesperson wouldn’t comment on AT&T’s lack of authorized unlocking option, but said this: