Our first plan was to go up to the crater and walk partly around it, but we had time so we did the whole circle. (3.2 km, about an hour 15 mins)
Walk up is steep but only took us 10-15 minutes. Then walking anti-clockwise it's a bit challenging going to the highest point. It's amazing seeing people doing this walk - and then realizing you're doing it too!
The crater seems bleak in pictures but it's so surreal and you can't help but feel overwhelmed. Then looking at the Dimmuborgir fields, it's all so amazing.
At the top it started raining really bad, and no where to hide... bring a good RAINCOAT and RAIN PANTS, or be like me and miss a third of the changing view due to fast walking back to the car...