If you searched for pictures of Iceland on the internet, you have found this iconic location. This is one of the easiest accessible locations in Iceland. The access is 24/7 all year long. The only think to have in mind, is the small parking lot at the main road. There is only a 200m walk from the parking lot to the main location where you can get the waterfall and the mountain in your frame.
Stokksnes is a beautiful location which is easily accessible from the ring road. The piece of land is private therefore you are requested to pay entry fee (currently 800 ISK) at the Viking Café. If the café is closed, you can buy your ticket via a vending machine directly at the entry to the Viking Café. You can scan the entry ticket to pass the barrier with your car.
This location is at any weather condition and any time wonderful for photography but take the right clothes. The wind can be very strong and cold.