• Java — Bromo (2,329m — iconic smoking caldera), Semeru (3,676m — Java’s highest, active), Ijen (2,443m — sulfuric crater with blue fire phenomenon), Merapi (2,930m — one of the world’s most active volcanoes)
• Bali — Agung (3,031m — sacred Hindu volcano), Batur (1,717m — popular pre-dawn crater rim walk)
• Lombok — Rinjani (3,726m — 3-day crater lake trek; one of Indonesia’s finest multi-day routes)
• Sumatra — Kerinci (3,805m — Sumatra’s highest and most active), Lake Toba, Leuser NP
• Papua — Carstensz Pyramid / Puncak Jaya (4,884m — Oceania’s highest; expedition with technical climbing skills required)

• Volcanic terrain — young, steep, often unstable ash and lava; sulfuric gas zones near active craters
• Rinjani crater lake (Segara Anak) — an emerald lake at 2,000m inside the caldera with a new cone growing from it
• Javanese agricultural slopes — terraced rice fields transitioning to volcanic forest below the summit zones
• Balinese sacred landscape — forested volcanic slopes; temple complexes embedded in the mountain approaches
• Papua jungle — dense equatorial rainforest approaching the Carstensz Pyramid; extremely remote

• Mount Bromo sunrise — iconic smouldering cone rising from the Sand Sea caldera; the most photographed landscape in Southeast Asia
• Ijen Blue Fire — one of the rarest natural phenomena in the world; only visible at night; plan arrival before 3am
• Rinjani Crater Lake (Segara Anak) — 3-day circuit; an emerald lake inside a massive volcanic caldera
• Carstensz Pyramid (4,884m) — the highest peak between the Himalayas and the Andes; one of the Seven Summits (Oceania)

• Easy (guided day visit) — Bromo (by jeep + short walk), Batur crater pre-dawn walk
• Moderate — Ijen blue fire night hike, Bali Agung (with guide)
• Hard — Rinjani 3-day circuit, Semeru summit, Kerinci: serious active volcano ascents requiring fitness and altitude preparation
• Extreme — Carstensz Pyramid: genuine expedition requiring technical rock and glacier climbing skills

• Most national parks: entry fee plus trekking permit at park gate (IDR 50,000–300,000 for foreigners)
• Rinjani (Lombok): permit plus mandatory registered guide; book through Rinjani Trekking Club in Senaru or Sembalun
• Semeru (Java): daily visitor quota; advance online booking required at booking.bromotenggersemeru.org
• Merapi (Java): access restrictions change with volcanic alert level — check BPPTKG Yogyakarta alerts before any attempt
• Carstensz Pyramid (Papua): special expedition permit from Indonesian government (months of advance paperwork); limited access by helicopter only

• Gas mask — mandatory for Ijen; buy locally at the trailhead (cheap and effective)
• Trekking poles — for Rinjani upper sections and Semeru crater approach
• Headlamp — essential for Bromo, Batur and Ijen pre-dawn approaches
• Rain gear — dry season (May–October) is best but rain still possible; wet season descents can be treacherous on volcanic slopes
• Guide — mandatory for Rinjani and recommended for all serious volcano summits

Emergency: 112 (national) | Police: 110 | Ambulance: 119

• SAR (Basarnas) operations exist but response times in remote areas can be very long
• Guides are mandatory on Rinjani and recommended for all multi-day routes
• Active lava zones at Semeru — do not approach the active southern crater (Jonggring Seloko) beyond the official exclusion zone
• Merapi summit — only permitted during alert level 1; check BPPTKG status before any attempt

• Active volcanic hazards — the primary specific risk across Indonesia; alert levels change rapidly
• Tropical rain — dry season (May–October) gives best trail conditions; wet season (November–April) trails extremely muddy on volcanic slopes
• Rinjani closed January–March — annual trail restoration; verify current closure dates before planning
• Heat and humidity — start all hikes before 6am to avoid tropical afternoon heat and storms

• Dry season (May–October) — best for Java, Bali, Lombok, Sumatra; clear skies; lower rainfall; best volcanic trail conditions
• Wet season (November–April) — heavy tropical rain; trails extremely muddy; some parks close; Rinjani typically closed January–March

• Jakarta (CGK) and Bali/Denpasar (DPS) — main international gateways
• Java volcanoes — fly to Surabaya for Bromo, Ijen and Semeru; fly to Yogyakarta for Merapi
• Lombok (Rinjani) — fly from Bali to Lombok (30 min); taxi to Senaru or Sembalun trailheads (2hr)
• Sumatra (Kerinci) — fly to Padang then road to Kerinci Seblat NP (6hr)
• Papua (Carstensz) — fly Jakarta → Timika then helicopter to base camp; no road access

• Indonesia requires drone registration with the Ministry of Transportation (Ditjen Hubud)
• Drones near active volcanoes strictly prohibited — volcanic ash clouds and unpredictable updrafts make flying extremely dangerous
• National parks (Bromo, Rinjani, Kerinci Seblat) — prohibited without special permit from the park authority
• Bali cultural/religious sites — deeply disrespectful and prohibited near temples; fines enforced