The iPhone 4 is the hottest gadget to have. It’s also the most difficult to get. The unlocked model is also more expensive and has a higher resale value when it’s time to upgrade.
Jailbreaking and using an unauthorized unlock is available. But future availability of these unlocks are not guaranteed. You may end up with a carrier-locked model and be stuck without an unlock for a long time.
Before buying an iPhone 4 from unofficial sources such as eBay, craigslist or classified ads sites, make sure that it is unlocked. Here’s a way to tell if the phone is carrier locked, based on the part number written on the box:
Locked iPhone 4 country part numbers
Germany
MC603DN/A – 16GB Black
MC605DN/A – 32GB Black
Japan
MC603J/A – 16GB Black
MC605J/A – 32GB Black
Spain
MC603Y/A – 16GB Black
MC605Y/A – 32GB Black
USA
MC608LL/A – 16GB Black
MC610LL/A – 32GB Black
MC318LL/A – 16GB Black
MC319LL/A – 32GB Black
Unlocked iPhone 4 country part numbers
Australia
MC603X/A – 16GB Black
MC605X/A – 32GB Black
Canada
MC603C/A – 16GB Black
MC605C/A – 32GB Black
France
MC603FB/A – 16GB Black
MC605FB/A – 32GB Black
Hong Kong
MC605ZP/A – 32GB Black
MC603ZP/A – 16GB Black
Italy
MC603IP/A – 16GB Black
MC605IP/A – 32GB Black
New Zealand
MC603X/A – 16GB Black
MC605X/A – 32GB Black
Singapore
MC603ZA/A – 16GB Black
MC605ZA/A – 32GB Black
Sweden
MC603KS/A – 16GB Black
MC605KS/A – 32GB Black
United Kingdom
MC603B/A – 16GB Black
MC605B/A – 32GB Black
Thanks to the following sources: TGIL, AppleI, AppAdvice. If you know of any other country part numbers, please let me know in the comments.