In the western part of Shiraoi, Kojohama (虎杖浜) is a coastal onsen town with quite ageing ryokan and minshuku along Route 36. Most travelers pass through the town and go to Noboribetsu Onsen, but this town is much-loved by locals and onsen enthusiasts. All onsen has 100% free-flowing hot sulfur spring and open for day-use to the public around ¥500. You can taste tarako (たらこ) at the direct sales shops in town.
(アヨロ温泉) The town’s most modern and popular onsen facing the ocean, with clean indoor and open-air baths. It is a 15-minute walk west from JR Kojohama Station along the coastal road.
More info www.ayorospa.com
(ホテルいずみ) On the coastal hill of western Kojohama is this onsen hotel, overlooking the ocean from Japanese-style rooms and open-air baths. You can play the park golf and walk on a footpath. The staffs will pick you up at JR Noboribetsu Station, 3km west away from here. Nonguests can use the baths for ¥600.
More info www.izumi-kojohama.jp
The onsen town is easily accessible on foot from JR Kojohama Station (虎杖浜駅), one stop east of Noboribetsu Station (4min) and four stop west of Shiraoi Station (17min).
Local buses run to Kojohama from Shiraoi (30min) and Noboribetsu Onsen (17min). Note that Kojohama Onsen (虎杖浜温泉) bus stop is about 2km east of the train station, facing the Hotel Hokuyo (ホテルほくよう: day bathing 5am-11pm) with a pleasant open-air bath.