Porto to Lisbon by bicycle, the coast in between

The direct route between Porto and Lisbon takes well under three hours by train and rather less by air. The coast road takes considerably longer, and passes through a run of small towns that most travellers moving quickly between Portugal's two big cities never see at all. A bicycle is, in this particular case, not simply the slow option; it is close to the only way of stringing all three together in a single unhurried week, since none of the three sits directly on the main road or railway line that the express services use.

A town built for seaweed

Aveiro, an hour or so south of Porto, is regularly compared to Venice, on the strength of the canals that thread through its centre and the brightly painted, high-prowed boats, moliceiros, that once worked them for a purpose considerably less romantic than gondola rides: harvesting moliço, a type of seaweed once gathered in bulk from the surrounding lagoon and used as fertiliser on nearby farmland. The trade has mostly gone, and the boats now mostly carry visitors rather than seaweed, but the canals and the pastel-fronted buildings along them remain, a working port town's infrastructure repurposed rather than replaced.

A canyon the sea can't see, and a beach that pays for it

Further down the coast, Nazaré has become known, in the last decade and a half, for waves considerably larger than anywhere else in Portugal produces, the result of an underwater canyon just offshore that funnels ocean swell into the bay and amplifies it dramatically as it reaches shallow water. The phenomenon has drawn big-wave surfers from around the world in winter, when conditions are at their most extreme, turning a quiet fishing town into an unlikely fixture on the international surfing calendar for a few months of the year. In summer, the same beach reverts to something closer to an ordinary Portuguese seaside resort, its cafés and fish restaurants doing a steadier, quieter trade than the winter crowds who come to watch, from the clifftop fort above the town, waves the size of houses.

A town given as a gift, repeatedly

Óbidos, a little further south again and set back from the coast, is smaller and quieter still: a hilltop town enclosed within its medieval walls, narrow whitewashed streets climbing to a castle at the top. From the thirteenth century, Portuguese kings developed the habit of giving Óbidos to their queens, as a wedding gift or a mark of favour, a practice that continued on and off for more than five hundred years and left the town with an unusually well-preserved historic centre, since royal property tended to be maintained rather than left to decay. The full circuit of the walls can still be walked today, giving a view down over the whitewashed rooftops that the queens who once owned the place would largely still recognise.

Cycling it, or letting a ship do the work

Explore's week-long cycling route follows this coast closely, covering Aveiro, Nazaré, Óbidos and Peniche before finishing in Lisbon, a pace slow enough to notice the fishing harbours and lagoons that the main road and railway bypass. For those who would rather cover the same stretch of coast by sea, Ambassador's Iberian Cities and Promenades cruise from Portsmouth calls at Leixões, for Oporto, before continuing south past this same shoreline to Lisbon, then on to Cadiz, Gibraltar and Vigo, seeing from the water much of what the cyclists see from the road.

Either way, the coast between Portugal's two great cities turns out to have plenty to say for itself, if the itinerary allows the time to listen. It is easy enough to fly between Porto and Lisbon and see neither the canals nor the canyon nor the walls; it is only slightly harder, and considerably more interesting, to go by the coast instead and let the towns in between earn their place on the map.