There are plenty of cycling routes with sea views. This one is different because the sea is not beside you: it is below you. For a good part of the day you ride tens of metres above the water, with ships passing through the strait right under your wheels.
01 Seventy kilometres above the water
The route links six islands of the inland sea and ends on the coast of the neighbouring island. The road measures 59.4 kilometres and contains 55 bridges; the cycling itinerary is somewhat longer because it does not climb straight up to each deck, but in loops.
The profile is kind. There are no mountain passes, and the climbing is concentrated in the ramps up to the bridges, which are designed for bicycles. The day's effort is not in the gradient: it is in the distance and the wind.
Between bridges you ride across the islands, and there the route is ordinary road, shared with cars, with a blue line painted on the tarmac marking the way. It is comfortable and well signed, but worth knowing: it is not a segregated bike path from end to end.
02 The first bridge is not crossed
Here is the first logistical surprise. The bridge linking the mainland to the first island has a steep climb and is not meant for cyclists, so the normal thing is not to cross it: you take a ferry from central Onomichi.
The crossing is minimal: it costs 110 yen per adult with a bicycle and several operators run it. In practice it works like a conveyor belt, with frequent departures and no booking.
That small detour changes the start of the day for the better. You begin by crossing the channel at water level, among shipyards and cranes, and only then climb to the first deck. The contrast between the two scales of the sea, the ferry's and the bridge's, is one of the best things about the route.
03 A lane slung under the roadway
On the bridges, the treatment of bicycles is not a strip painted at the edge of the traffic. In some cases the path runs on a level of its own, slung beneath the roadway and inside the structure; in others it runs to one side, physically separated from the cars.
The sensation is odd and very good: you ride down a quiet corridor, traffic overhead and the strait opening out between the struts. On some bridges the corridor is so straight and so long that it disappears from view.
To get up there, there are the ramps, the design detail you appreciate most. Instead of attacking the height head on, they trace long curves across the hillside, so that climbing forty or fifty metres is done without leaving the small chainring.
04 Four thousand one hundred and five metres of bridge
The most impressive one is at the end of the route and measures 4,105 metres. It is not one suspension bridge but three linked together, with six towers and four anchorages, and a shared anchorage joining each span to the next.
Halfway along is the other, a cable-stayed bridge of 1,480 metres with a 890-metre main span and 220-metre towers shaped like an inverted Y. When it opened, in 1999, it had the longest cable-stayed span in the world, and kept it until 2008.
Three suspension bridges in a row, six towers and four anchorages: four long kilometres without touching land.
That detail matters for the ride, and not just for the photo. A four-kilometre deck with no intermediate exit means that, once up there, you cross the whole thing. If it is windy, you cross in the wind; if the sun is hard, there is no shade until the far shore.
05 The toll, the rental and the way back
The bridges carry a toll for bicycles too, around 500 yen for the whole route, collected at booths at the entrance to each lane. That toll, however, is waived for cyclists until 31 March 2028 as a promotional measure, so it is worth checking the situation before you set off.
Rental is the easy part. There are around ten terminals spread along the route and you can return the bike at a different one from where you picked it up, which is what makes it possible to ride it one way without retracing your steps.
The exception is the good kit. The road-bike operator has only two terminals, requires a booking in advance for the drop-off at the far end and charges a 3,300-yen supplement for it. If you want a light bike and to finish on the other island, budget for it.
06 How to put it together
The standard version is one day: an early start from Onomichi, the ferry, and arriving on the far coast in the afternoon. It is a route an experienced rider completes without trouble, but with stops, lunch and photographs it takes the whole day.
The version that almost always works better is two days, sleeping on one of the middle islands. It spreads the kilometres, it allows detours off the main line onto coastal roads and, above all, it gets you onto the bridges early and late, which is when the light is worth it.
And two specific warnings. First, the month: October and November bring 7.1 and 6.9 rainy days, against June's 11.9, and they avoid August's heat. Second, the return: the route ends on another large island, so decide before you leave whether you come back by bus, by boat or by sleeping there, because improvising it at the end of a tiring day is expensive.
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