I am headed to Bali and am quite interested in doing a sunrise volcano trek. I have read a little bit about Mount Agung and a little bit about Mount Batur. While Agung is higher, I'd like to know which is the more interesting and challenging trek.
Also does it need to be booked in advance?
Mt. Agung is definitely the most challenging and I would say the most interesting too.
You can easily arrange the trip from Bali, so no need to book in advance. If you are going any time soon it is going to be in the wet season, so it might be impossible to climb on some days due to bad weather and muddy tracks, but you probably wont know that until the day before the climb, so its a god idea to have a flexible itinerary.
Also if it's possible to climb Agung around full moon that is preferable.
If you want a little longer trekking trip I can recommend Mt. Rinjani in Lombok. The normal route is a 3 day trek and the views from the summit are truly spectacular and it is a great trek - can only be done in the the dry season. almost 7 years ago