First of all you need to know that Aso Caldera is huge and diverse. Think of it more as a larger area rather than a single volcano. There are fields and farms, hot springs, waterfalls and wonderful roads winding up and down the hills, offering fantastic views all the time. On the other hand there are several other craters inside Aso Caldera and that’s where the volcanic desert is predominant.
The main attraction is undoubtedly Naka-dake, the remaining active crater. I assume the experience will be different every time, as the volcano constantly changes, but it was quite a spectacle when I was there. If you want to feel and see the power of nature, you have to go there and have a look into this huge steaming crater, emitting fumes and gases with an intensity that is almost scary. Take some binoculars, so you can explore the crater floor a bit better, and have a look at the short video, as this is hard to express in words.
You can go right up to the rim of the active crater, by car or bus. The main road ends at a parking lot next to an old and not very promising looking ropeway terminal. I didn’t see the gondola running, but you don’t really need it, as you can walk up to the rim. It takes about 10 minutes on a well-maintained and not very steep paved path. Otherwise, you can continue by car, but there is a toll of ¥600 for the last stretch of road.
For most people the discovery ends here. They have a quick look into the crater and that’s it. It is a shame, as there is so much more to it. You definitely should not miss the volcanic desert right next to Naka-dake, another truly unique experience. There is a separate article giving you more details. Please check it out.
Geoparks Japan has also launched a few itineraries covering different topics. These are self-guided tours, which you can download from their website (Geo Tourism Courses). Please also visit the very helpful tourist information desk at Aso Station, as they will have the most up-to-date English language information about the status of the volcano, train and bus schedules etc.Other fantastic excursions include the wonderful plateau Kusasenri-ga-hama (草千里ケ浜). It is an extensive open grassland with a couple of ponds and grazing cows and horses. A short hike from here you can reach Kijima-dake (杵島岳, 1270m) which also provides awesome views across the entire Aso Caldera, including Komezuka (米塚), a perfectly shaped and therefor very prominent extinct volcano cone. Eboshi-dake (烏帽子岳, 1337m) is another peak from where you can marvel at the surroundings from yet another perspective.
The most convenient way to get around is by car, so that you can discover in a more flexible way. Buses of course serve the main attractions, but they are not so frequent.
When to go? At the beginning of April it was still pretty cold, but there were enough hot springs to warm me up again! However, some areas probably look more fascinating as soon as spring has switched on the lush green colors, especially around the Kusasenri-ga-hama plateau.
Where to stay? I can highly recommend Shukubo Aso, a wonderful farmhouse closed to Aso Station. There is also a budget-friendly backpacker hostel called Aso Base Backpackers.
How much time to spend? I would say at least 2 days, 3 days if you want to go for a hike or two. In case you have only got a day to spend (like me), that’s still worth it, but I would have loved to have a bit more time.
Depending on the constantly changing volcanic activity, the access to the active crater might be denied. However, as I said, there are plenty of other things to do and the views from afar are not to be missed either. Please enjoy and let me know any questions in the comments.