Pirttikoski- Riisikkala- Urjala- Kylmäkoski. Length circa 70 km
The downstream paddling route of the Tarpianjoki River can be started, for example, at the bridge located where the river flowing from Lake Uurtaan meets road No. 13687. The current is calm and widens to about 10 meters at the point where the Uperojoki River joins it. The first lake encountered is Kallijärvi, whose narrow strait connects to Lintujärvi. On the Lintujärvi side, the lake is cut across by a 2–3 meter high, 5 meter wide reed bed. The passage is hard to find, but it is on the left side in the direction of travel, about 100 meters from the shore. From Lintujärvi, the river flows calmly towards Simola, where there is a dam at the road crossing the river. From the dam basin, the river route continues gently for several kilometers past the Riisikkala bridge. Next comes the one-kilometer-long Tampinkoski rapids. Because of the dense forest along the banks, Tampinkoski is best bypassed overland. Suitable field roads can be found. After Tampinkoski, the river calms down again, joining on its way with the river flowing from Lake Kortejärvi in Urjala, and flows 10–15 meters wide to Kylmäkoski, and from there all the way to Lake Jalantijärvi. The river route flowing out of Jalantijärvi ends in Lake Vanajavesi.
