These days the question is not whether someone can indeed tap your cell phone, it is whether this activity is legal. Cell phone technology has come to a place of making it possible and even fairly easy to tap someone's cell phone, even the newest iPhones. A variety of software programs exist for this purpose that are easily installed on someone's iPhone, but you must be able to get the phone in your possession long enough to enter the product code and accept installation of the software on the iPhone you wish to tap.
Checking the Battery
Check the battery life often. If someone is listening in on your conversations or covertly looking at your text messages, this activity consumes cell phone battery life quickly. If your cell phone battery seems to be going down too quickly, this could be a sign that someone has tapped your phone. The battery may also seem warm even when it's not in use. Each time your iPhone is used, whether by you or by a cell phone tap, the battery heats up and is noticeably warmer.
Listen for strange noises in the background. If someone has tapped into your cell phone and is listening covertly, there will be unusual background noises, such as static or strange clicks and beeps. Stop your conversation and listen carefully to make sure these aren't simply common noises associated with being in a poor coverage area or an elevator. If you live in a remote area where cell coverage isn't good, you may experience static at certain times simply because strength from the nearest cell tower is low.
Monitor any odd phone activity. Should your phone suddenly come on, make weird sounds or behave strangely, this could be a sign that your phone has been tapped. When such activity occurs, pick your iPhone up and check the battery. If it feels warm, this could signal that someone is attempting to remotely listen in on your conversation. Cell phone tapping can utilize your cell phone as a listening device. A person miles away can hear your conversations even when you aren't on the phone and the phone is nearby.
Watch for peculiar text messages. Should you receive a garbled text message that makes no sense, this could be evidence of cell phone tapping. Text messages with sets of numbers or coded messages may also signal the presence of a tap on your iPhone. Check to see who the sender was and try to contact this person. If you are unable to text or call the sender back, this may mean your iPhone has been tapped.
Check your phone bill regularly for clues as to whether someone has tapped your iPhone. You may notice unexplained charges for text messages. You might also check the length of time for your phone calls. Unusual charges on your cell phone bills are a good way to verify that your iPhone has been tapped.