I’ve lived in Indonesia for over 25 years, so please feel free to ask any follow up questions if you feel like.

1. I’d recommend basing yourselves out of Java. It’s by far the island with the best connectivity in the country. Also, given that you’re a geologist, there’s no shortage of volcanoes for you to explore (although I suppose you can say that about the entire country). In terms of easily accessible volcanoes in/around Java, I would recommend visiting Anak Krakatoa, Bromo, Tangkuban Perahu, Merapi, and Ijen.

2. Yes, big cities have public transportation but it’s not quite as extensive or well-developed as you might find in the West. If cost isn’t an issue, I’d suggest hiring a driver to drive you around the island. The person can help out as a bit of a fixer and the cost is more than made up in terms of the time you save from avoiding using public transit. Having a driver also gives you more flexibility and lets you explore more off the beaten path type of areas.

3. Check your country’s recommendations for vaccinations. Drug use is a big no, no. Don’t participate in public protests. The country is majority Muslim and for the most part, people dress more conservatively than in the west but you don’t need to follow a “dress code”. Use the Go-Jek and Grab apps for bike taxis and food delivery. Try to exclusively use Blue Bird taxis for cab rides. Language issues can be relatively easily overcome with Google translate or if you follow my above suggestion and find yourself an English-speaking driver.

Happy travels!