View all your content on a stunning 5-inch Full HD Super AMOLED™ display that's powered by a robust 1.9GHz quad-core processor — all in a light 0.29LB smartphone.
Take it at Your Own Pace:
Easy Mode is a setting you can use to simplify your home screen with bigger icons and your favorite apps, so you can take your time to discover the amazing world of your new Galaxy S 4.
What's an unlocked phone?
It's basically a mobile phone that's not tied to a single network or service plan at the time you purchase it. You simply buy the phone and then get it connected to any compatible network and service plan you choose. An unlocked phone needs a SIM card from a communications service provider or carrier before it will work.
What's a compatible network?
Unlocked phones use either CDMA (Code Division Multiple Access) or GSM (Global System for Mobile Communications) networks with an interchangeable SIM card. The GSM network is used by AT&T and T-Mobile while the CDMA network is used by Sprint and Verizon. When you buy your unlocked phone, make note of which networks it can utilize so you can find the appropriate service provider.
What's a SIM card?
A SIM (Subscriber Identity Module) card is a small, removable plastic card with a chip that holds personal information such as your phone number, address book, text messages and more. The SIM card also includes a security key with authentication information that specifically identifies the phone. Typically, an unlocked phone will not include a SIM card. You'll likely receive one through your carrier when you connect your phone to a new or existing service plan. Regardless of the SIM card's origin, the unlocked phone will recognize it and start sending voice and data over the network.
What are the advantages of an unlocked phone?
The first big advantage of an unlocked phone is that you're not limited to the small selection of devices that a particular carrier offers. You get to choose your unlocked phone from any of the available mobile devices that have a SIM card slot and are compatible with your network.
Along those same lines, you can buy an unlocked phone and add it to your current service plan without requiring a new contract. (Note that bringing the unlocked phone to a new carrier will most likely require you to sign a contract with that carrier.) You can take any SIM card from any carrier and put it in your unlocked phone as long as the phone is compatible with the network and bands. So, if you sign up your unlocked phone for service with AT&T and decide later to switch it to T-Mobile, you can still use the unlocked phone you originally purchased.
And with an unlocked phone, you don't need to wait for your contract to expire to upgrade your phone. Instead of waiting for your contract renewal to get a new phone, you can purchase an unlocked phone and use it now on your existing service contract. The added benefit is that when your current contract is up, you'd be free to cancel your plan and switch to any network or carrier you wanted – taking your phone with you to your new plan and carrier! You could also purchase prepaid plans so you'd have no monthly fees.
One last thing for you international travelers: With an unlocked phone, you'd be able to purchase and install a new SIM card from a carrier operating within your destination country so you could avoid paying the astronomical roaming charges associated with using a mobile phone outside the United States. And maybe you just want to purchase a cheaper unlocked phone for your trip and leave your expensive phone at home to keep it from getting lost, stolen or damaged.
What are the disadvantages of an unlocked phone?
When purchasing a new "locked" phone, the carrier often subsidizes the cost of the mobile phone. (They're making money off the service plans and other add-ons, not the device itself.) So an unlocked phone does not benefit from the subsidy offered when bundling the phone with a carrier contracted plan. You're responsible for the entire cost of the phone up front.