There are a myriad of reasons why you may need to get your hands on someone else's cell phone records, but it's not possible in all cases. Right now, you can only legally get cell phone records from someone else's phone if there is a matter currently filed that requires the records for discovery purposes, if a person goes missing and you need to find out who they last spoke to, or if the records are yours or an immediate family members.
Requesting Records of Family Members
If your family members are on the same plan as you then all you need to do is call your mobile company and request the cell phone records for the month(s) you want to review. There may be a charge to get a copy of the records on paper. If you receive a monthly bill in the mail already, save yourself the effort and the cash and go through the bill; most companies provide a complete, detailed list of every phone call that was made, to whom, for how long, and what date and time along with your bill for the month.
You can also set up an account online to track your family's phone history. Visit the website for your mobile company, and fill in your name and cell phone number. A text will go to the phone you are setting up an account for, so make sure you have the phones on hand before signing up and have text messaging enabled. Once you fill in the code you received by text, you'll be able to set up a username and password that you can use to get the cell phone records in real time. You will also be able to see what phone number was contacted, and the location of the phone's owner by town and state. This enables you to call any suspicious numbers directly to get to the bottom of the situation.
Requesting Records of a Missing Person
If someone goes missing or is suspected of being kidnapped, you can call the phone company to not only get their cell phone records, but possibly ping their cell phone to see exactly where the phone (and usually the person, if the phone is on them) is located. To do this, you may need the help of the local police. Either call yourself and explain that the individual has gone missing and provide a copy of the police report by fax or by e-mail, or request a police officer make the call instead. The cell phone company will provide you with the times of the most recent phone calls and texts, and the phone numbers they were made to. They can also track the location of the phone by tracking what towers were used when the last phone call was made, or ping the phone using their GPS system to see where the phone is now if it is turned on.
Request Records in a Court Case
If you are currently in litigation with another person, and the case warrants it, you can get cell phone records of the opposing party by way of a subpoena. This only works when the cell phone records are relevant to the situation, i.e., to prove you spoke with the person at certain dates and times, to show the person was in a location different than what they are claiming, and so on.
To subpoena phone records, you would use a Subpoena Duces Tecum, and request any cell phone records in the month prior through the month after the time period you would need to review. For help with writing and serving subpoenas, check the "Resources" section of this article for links to more articles on subpoenas and the discovery phase.
Use a Phone Records Service
There are quite a few websites online that offer services to get cell phone records for you. These websites can find cell phone records for just about anybody who has a cell phone. They are moderately expensive, costing anywhere from $50 to $250 for anywhere from a month to one year of records. Use these services sparingly, and only when you absolutely need to, like for one of the above reasons when contacting the cell phone company directly proves fruitless. There is an ethical issue with using cell phone record services, and although using them is not illegal, misusing the records you receive from the company can be.