Question: I booked a flight to Kish Island and was planning to chill out a few days before exploring the more interesting parts of the country I was wondering wheather this could lead to any difficulties because of Kish beeing excluded from the Visa obligation. I´m not sure if my Visa will expire when I leave the main land for the Island?

Answer: Kish is a 91.5 km² resort island in the Persian Gulf. It is part of the Hormozgan Province of Iran. After Sharm el-Sheikh and Dubai, Kish Island is the purported to be the third most visited vacation destination city in the Middle East.
Foreign citizens wishing to enter Kish Free Zone from legal ports are not required to obtain visas prior to travel. Valid travel permits are stamped for 14 days by airport and Kish port police officials.

For Iran visa check this page:  http://www.uppersia.com/Iran-travel-services/iran-visa.html