I decided to extent my visa in Isfahan since it is only in the larger cities possible. As in other cities you therefore need to go to the Tourism Police. The officials extend the visa only if it is almost expired – but if you need to extend it earlier I recommend you to say that you want to an area where you can’t extent it, e.g. desert. In general, do not to take a local friend as a translator and act as the stupid tourist. Locals and officers will be glad to assist you if you look disorientated and helpless enough. This way I could skip most of the lines and when they let you wait to long just start to knock at the windows or doors. Some basic words in Farsi or naming the most famous football team/player of your country helps you to win the officers sympathy – although it always depends on the officer. You are sent to more than 6 counters to get different forms and signatures as well as to a bank at which you need to pay something around 10€. The whole process can take quite a while and to be sure I would plan for the whole action with half a day. Keep in mind, that they are gonna do a lunch break at some point and that you can not take your phone inside the building – so write all the necessary information like your hotel address on a piece of paper before you enter. You need to bring 2 passport photos, photocopies of your passport and the entrance visa and your passport, obviously.