The weather in Koya tends to be hot and humid in the summers with temperatures in the mid-80's (Fahrenheit) and get a good amount of rain. Koya also experiences typhoon season during September, so it's best to avoid the area during this time. Winters are fairly mild and stay in the mid-40's. The best times to visit are spring and late autumn when there is less rain and the temperatures stay in the high 60's.
SightsOne of the most famous attractions in Koya is Oku-no-In, the mausoleum of Kukai which is illuminated by thousands of lanters. Legend has is that the lanterns have been lit since Kukai's death, which was over 1000 years ago. The mausoleum is enclosed by a large graveyard that has winding paths and some very unique gravestones, such as, giant spaceships and a monument built by a pesticide company memorializing its insect victims.
A popular site is the Garan, a temple complex that is home to the Konpon Daito pagoda. The Shingon doctrine says that this pagoda represents the central point of a mandala that covers all of Japan. Explore the stunning garden of the Kongobu-ji Temple, which also happens to be the headquarters of the Shingon sect. The price of admission here also includes a rice cracker and a cup of tea.
NeighborhoodsKoya is essentially made up of the city at the bottom of the mountain, and the mountain itself. The mountain is home to a few different attractions, including a golf course and small shrines. The city houses the university, shops, restaurants, and the majority of the temples.
Just outside of Koya is the city of Otaki, which is famous for the large waterfalls located at the entrance of the city. Otaki is a picturesque spot for a day trip to walk around the waterfalls and enjoy a picnic.
ActivitiesNaturally, the most popular activity in Koya is hiking Mount Koya. There are plenty of hiking trails, one of which begins at the large gate of Daimon that leads you to a shrine at the top of Bentengaku. The top of Mount Koya provides stunning views of Wakayama city and the ocean, making it the perfect spot to stop for a picnic before heading back down.
Food and DiningIf you plan to stay in a temple, you should plan to be eating only vegetarian dishes as the monks in Koya are all vegetarian. A local specialty is Koya-dofu, a tofu dish that involves freeze drying then reconstituting the tofu for an entirely unique taste. If you don't think you could go completely vegetarian, don't worry, there are plenty of options for you. The Inoue is a popular restaurant that has the largest Om-Rice in Japan, Om-Rice is an omelette filled with rice and meat. There are also plenty of traditional izakaya, pubs, around who offer classic Japanese pub food and offer a relaxed atmosphere and a great place to meet locals.
TransportationTrains are one of the easiest options for getting into Koya and vary depending on the area you're coming from. The most popular option is the Nankai Electric Railway which takes you from Osaka to the Gokurakubashi station. Japan Rail is another option if coming from Kyoto. Once you arrive in Gokurakubashi, you take a cable car up to the top, then a bus into town. While this sounds complicated, this entire system is extremely well organized with the train, cable car, and bus schedules integrated so well that you often only have to wait a few minutes for each mode of transportation.
If you're feeling rather adventurous and wanderlust, you can take on the Choishi-michi pilgrimage trail that begins in the city of Kudoyama and runs through Koya. This is an ancient trail that takes about 7 hours to walk in total, though there are many observation huts along the way that allow pilgrims to camp in overnight. Getting around the city itself is extremely easy as everything is within walking distance.