How to Find Out Someone's Sprint Cell Phone Number for Free

1. Check your landline caller ID or your call phone call logs if the Sprint customer has called you in the past. Unless the Sprint customer manually blocks their outgoing caller ID, you will receive this information when they call you. Landline caller ID stores multiple numbers at one time. Most cell phone call logs store at least the last 10 numbers.
2. Check you cell phone bill. Most cell phone bills list detailed incoming and outgoing call details including the phone numbers. This is helpful if the numbers are no longer stored on your cell phone call logs. Most cell phone provides give you access to at least 12 months of your bills via your cell phone online account.
3. Press #NUM# into the keypad of the Sprint customer's phone to obtain the number. Of course, this only works if you have access to the mobile phone. This is a good way to obtain a number if you found a lost Sprint phone and you are trying to locate the device. If the phone happens to be a BlackBerry, you can press the green phone button and look at the top number under, 'My own Number.' This is the number for the Sprint customer.
4. Check social media websites, such as MySpace, Facebook and Twitter. Many Spring customers use their cell phone as their primary contact information and in many cases, they list their contact information on their personal social media pages.