Akan National Park

The park's attractions are its three sparkling clear mountain lakes, the eponymous Lake Akan (阿寒湖 Akan-ko) to the west, Lake Mashū (摩周湖 Mashū-ko) to the east and Lake Kussharo (屈斜路湖 Kussharo-ko) between them. The largest settlement nearby is Teshikaga (弟子屈), to the south of Lakes Kussharo and Mashu.

Buses are infrequent and cover only the main routes. A rental car will come in very handy here.

A 2days pass is available at hotels, convenience store and train stations. It gets you around the area with Eco-friendly buses (run on bio diesel fuel) and it's also valid on the JR Senmo line between JR Mashu and JR Kawayuonsen. More info here.

• 🌍 Lake Akan (阿寒湖 Akan-ko). The best-known of the trio, largely thanks to mysterious fuzzy green algae balls known as "marimo", which you can view at the free visitor's center. There is also a small Ainu museum and lacklustre dance performances in the village of Ainu Kotan. 
• 🌍 Lake Mashū (摩周湖 Mashū-ko). Entirely protected, without a single building along its pristine shores, Lake Mashu can only be viewed from two designated lookout points, known as #1 (the larger and busier of the two, on the south shore) and #3 (on the north shore). A deep volcanic caldera lake, the lookout points are suspended high on cliffs above, and the bonzai-esque appearance of the gnarled trees nearby are a testament to the strong winds that seem to blow incessantly. Often blanketed with a thin layer of fog. Starkly beautiful and worth a visit.. Parking at # ¥410, parking at #2 free. 
• 🌍 Kaminoko Pond (神の子池 Kaminoko-ike). Literally "Child of God Pond", this is a small pond in the middle of the forest, reachable only by a long dirt track (no 4WD needed). What makes the bumpy trip worthwhile is that the water in the pond is a truly unearthly shade of transparent sapphire blue. The track is a few kilometers north of the Ura-Mashuko (#3) lookout. 
• 🌍 Lake Kussharo (屈斜路湖 Kussharo-ko). Also a caldera lake, but a bit livelier than the others as the volcanic peak of Mt. Wakoto (和琴山 Wakoto-san, 266m), jutting out from the southern shore, still bubbles, hisses (and stinks) with geothermal activity. An easy trail runs around the island. Good swimming in the summertime. 
• 🌍 Mt. Iō (硫黄山 Iō-zan) (5 minutes north of Kawayu by car). Literally "Sulphur Mountain", which is a fairly good hint of what you will see and smell if you go poke around the hells (jigoku). It is also called "Atosanupuri" by the Ainu (indigenous people of the Nord of Japan and nearby Russia). 

• Canoeing along the nearby Kushiro river is a popular if expensive activity, with a 90-minute guided trips from ¥5500.
• These hot spring resorts offer, surprise surprise, hot springs:
  • 🌍 Kawayu onsen (川湯温泉) (near Lake Kussharo). (updated Aug 2016)
  • 🌍 Akan-ko onsen (阿寒湖温泉) (at Lake Akan). (updated Aug 2016)
  • 🌍 Nonaka Onsen (野中温泉) (from the junction of Highway 240 and Highway 241, take Highway 241 SW several kilometers, turn SE onto Highway 861, follow this uphill for several kilometers, and the onsen is on your left), ☏ +81 1562 9-7321, fax: +81 1562 9-7164, nonakaonsen@ipstar.ne.jp. 09:00-20:00. This hotel and onsen has three onsen buildings — choose which one you want to enter when you buy your ticket. Two of the three buildings have outdoor baths.. Adults ¥350, kids ¥200, or cheaper. 
• There are many excellent hikes in the region.
  • In summertime at the Akan Kohan ski ground (阿寒湖畔スキー場), there are two interesting short hikes, one 550-m, the other 2.2-km. The shorter one takes you to a ski slope with an excellent view of Lake Akan, its islands and the surrounding forest. The longer one starts off climbing about 900 m up a ski slope before delving into the surrounding forest and taking you past a hot water creek (47 °C), and several bokke (ボッケ), an Ainu word referring to hot mud caused by volcanism.
  • Another hike from the Kawayu Onsen Visitor's Centre to Iwo-san (2.4 km) is a very flat and easy but extremely interesting one starting off in luxuriant forest on a moss path before petering out into desert-like scrub as you approach the poisonous vapours of Iwo-san.
  • 🌍 Mt. Meakan (雌阿寒岳) (the most convenient trailhead is next to Nonoka Onsen). Mt. Meakan makes for a nice day hike. There are several courses, and this is the simplest. Park your car at the trailhead 50 m SW of Nonoka Onsen. The trail starts 50 m NE of Nonoka Onsen. The trail goes up and around the back side of the volcanic mountain. On a clear day, there are good views of a pond inside the crater, but this can be covered by steam or clouds. From near the top, a side trail leads to Akan Fuji (阿寒富士). The loop continues downhill to Onneto (オンネトー), where you can walk along the road or around the lake to get back to the parking lot. This 8-km hike takes 5 hours at a casual speed.. 

On the shore of Lake Akan, the small village of Ainu Kotan is home to one of the largest concentrations of Ainu artisans in Hokkaido. There are numerous galleries and studios selling textiles, paintings and carved works for the well-heeled.

• 🌍 Mashūko Youth Hostel (摩周湖ユースホステル) (take a Bihoro/Kawayu-bound bus from JR Mashu station), ☏ +81 1548-2-3098. A very friendly youth hostel halfway between the town of Mashuko and the lake. Included in the price are homemade cakes and yogurt after dinner and all-you-can-drink milk in the morning, fresh from the neighboring farm — and you can even go squeeze your own glassful in the morning!. dorm: ¥3500-4700 ; about the same for room for 2 to 4; single room: ¥4900-6400; high and very high season in various period from July to October, normal rate the rest of the year. 
• Wakoto Peninsula Campground (和琴半島キャンプ場 Wakoto-hantō kyanpu-jō). Located on the shore of Lake Kussharo with Mt. Wakoto steaming in front. Facilities include free (but very basic) open-air and indoor hot spring baths to soak in. There is also a restaurant nearby with dishes ¥500 and up. ¥400 per person. 
• 🌍 Lake Akan Tsuruga Resort Spa Tsuruga Wings (formerly Akan Yuku no Sato Tsuruga, Japanese: あかん遊久の里 鶴雅). Located on Lake Akan, this modern ryokan hotel has open outdoor baths where you can view the lake, or several indoor baths which are varied and quite nice. There are a variety of rooms for those that prefer Western style, or they have 'semi-Japanese' style as well.. 
• 🌍 Nonaka Onsen (野中温泉) (from the junction of Highway 240 and Highway 241, take Highway 241 SW several kilometers; turn SE onto Highway 861, follow this uphill for several kilometers, and the onsen is on your left), ☏ +81 1562 9-7321, fax: +81 1562 9-7164, nonakaonsen@ipstar.ne.jp. This hotel and onsen is in the mountains at the base of a hiking trail for Mt. Meakan. Adults ¥7350. 

• You're already almost at the end of Japan, so why not head north to the outermost point of all, Shiretoko National Park?
• Bihoro Pass, a scenic drive on the way to Bihoro, may be worth a drive.