Most people enter the Iya Valley from the Oboke area by way of train (via JR Oboke Station) or by way of car/bus (via Rt 45, which leads in from JR Oboke Station). For sure, this is the fastest, easiest, and most common route, but it is not the only way in, nor is it the most scenic. Other less common routes offer some spectacular opportunities!
If going via Ikeda in the north, a great option would be to drive in on the old Iya Highway
(Prefecture Rt 32) from Iyaguchi which goes through the rugged Iyakei Gorge. The mostly one-lane road along here twists its way in upon the cliff faces, with stunning views from points like the Peeing Boy Statue
and Hi-no-Ji Bend.
Even more daring would be to enter through one of the remote mountain pass routes
by car or even by bus. All routes listed below are detailed on the
Transport Page (check here for "Local Travel by Car" under "Driving in Oku-Iya", or "Local Travel by Bus" under "Oku-Iya Seasonal Buses")
If coming/going via the north or east, the pass along Rt 439 (connecting from Rt 438) at Minokoshi
takes you past the trailhead of Mt Tsurugi.
Or opt to come in above Ochiai Village
to/from the north via the 1520m Ochiai Pass
along Rt 44. Amazing views await.
And if traveling via Kochi Prefecture in the south, consider taking the secluded Kyobashira Pass
along Rt 439.