Is calling a cell phone number long distance if it is a different area code?

It depends on your calling plan. If you are calling a mobile phone (cell phone), the cost depends only on the telephone number, not on where the mobile happens to be physically located at the time you call. For example, if you are using a landline in Napa, California, calling a cell phone with a number from Eureka, California, they are both in area code 707, but not within the same local calling area. Toll charges will apply for the call, unless you have a calling plan with a larger local calling area (or unlimited nationwide long distance).