While it's best to call Sprint directly to verify an ESN, you can check the ESN for your Sprint phone or data card over the Internet. It's more convenient than calling customer care, especially if you need to check multiple ESNs. If the phone's ESN is tied to an account with an outstanding balance or has been reported lost or stolen, you cannot reactivate the phone on Sprint service. The ESN is an identification number specific to each individual handset. No two phones have the same ESN, even if they are the same model.
Locate the ESN number of your Sprint device. You can find the ESN of your phone on the sticker under the battery, or for your PC card, on a sticker on the bottom.
Open your web browser and go to the free site www.checkesnfree.com.
Type the ESN in the box at the bottom of the page and press the "Check ESN" button.