If you want to call a mobile phone, be sure to have plenty of coins at hand (10 or 100 yen coins), or a phone card (there should be a vending machine nearby), put them/it in, and dial the full mobile phone number starting with 0X0 (The X may be 8, 9, or 7 depending on the receiver's number). If it's a regular landline phone number, start with the area code (for example, 03 for Tokyo).