We climbed Gunung Api twice around New Year 2012.

This webpage has a clear map of the area, showing Pulau Gunung Api, with Banda Neira, the main transport and commercial hub of the Bandas, right beside it.
http://www.liveaboards-indonesia.com/destinations/banda_islands.htm

There are a few fishermen’s houses but no homestays on Pulau Gunung Api, so you’ll need to overnight in Banda Neira.

(Actually you’ll need to stay a few nights in Banda Neira. Flights from and to Ambon by Nusantara Buana Air ran twice weekly in 2011 but were suspended at the start of 2012. Pelni ships pass through 2 or 3 times a week, in transit between Ambon and destinations elsewhere in Maluku and Papua. We recommend staying at Vita Guesthouse and eating at Mutiara.)

From Banda Neira, charter a ketingting (motorized canoe) from the ketingting dock near the Delfika 2 guesthouse, or get your guesthouse to arrange one (10,000rp round trip). Cross the strait (3 minutes) to the dock on Pulau Gunung Api and arrange a pick-up time with your boatman.

We allowed three and a half hours, comprising 2 hours ascent, half hour summit wandering and 1 hour descent. 3 hours would be ample for speedsters, 4 to 6 hours for slower hikers. Casual tourists without hiking shoes or legs should probably give this a miss as the trail is steep and pebbly, with too few hand supports for comfort.

Take loads of water. Paleskins will need dollops of sunscreen as the scrubby forest has lots of exposed patches.

Routefinding is easy; follow the upward path from the dock! There’s a shelter ten minutes up, a few metal signs along the way and great views back toward Banda Neira. The middle third is the steepest. At 500m you emerge from the forest, and then reach the lip of a shallow crater, which you skirt to reach the top at 636m. The summit is on the edge of a precipice, so don’t walk straight over! There are small fumeroles and warm rocks but no hints of an imminent eruption.

Be careful not to lose your bearings in mist while touring the crater area. We made our first ascent at crack of dawn and our second in late afternoon, but ended up in cloud cover both times! In fine weather the view should extend across the entire Banda archipelago. The top seemed to be clear for at least part of every day, so the best tactic might be to climb up in the morning and wait as long as necessary for a clear view; you could hail a ketingting from the shore for the return crossing to Banda Neira.

While you’re staying on Banda Neira, you can also climb Gunung Papenburg (247m), the highest point on the island.

Follow the west coast road out of town, pass the airport runway, then take the concrete path on the left up to the blue pumping station. Fork left into the forest, pass the ruined house and head up the ridge.

An alternative route is to continue past the concrete path for a further 1 km, where there is a road on the right and a well-defined path into the forest on the left. Take the path into the forest, turn left at the crossing after 200m, then after 200m fork left. This path brings you onto a ridge on the east flank of the hill, joining the main ridge near the top at a nutmeg plantation.

On either route the best views are on the way up. The path terminates at a gravesite twenty meters below the summit, which is accessible but wooded on all sides.