Leaving Porto with the Atlantic still in your lungs, you follow the Douro eastward and the city quickly dissolves into something quieter and older. The first two days track the riverbank fairly closely, and the riding is genuinely lovely — terraced vineyards stacked above you, the water green-brown below, the occasional quinta tucked behind iron gates.
From Porto to Pinhão, around 130 kilometres, the route is moderate enough that you can arrive somewhere civilised each evening. There are stretches of dedicated cycling path, particularly in the lower valley, though you will share regional roads for good chunks of the journey.
Surface quality varies: sealed tarmac transitions to rougher asphalt and occasional compacted gravel as you push east, so a gravel or touring bike with 35mm-plus tyres handles it more comfortably than a road bike.
East of Régua the valley starts to flex its muscles. The river bends tighten, the schist villages cling to hillsides above you, and the climbs become serious — short but steep, with gradients that can touch 12–15% on the quieter back lanes. Total elevation gain across the full route runs well over 6,000 metres if you follow the more scenic inland variants.
Riders typically budget eight to ten days, which allows time to linger at a quinta tasting table without arriving at your next albergue or rural guesthouse in the dark.
Crossing into Spain, the landscape dries and opens. The vineyards give way to cork oak and wheat plains, and Salamanca arrives as a reward: golden sandstone, students in the squares, and the best meal you have eaten all week.
Bike hire is available in Porto; consider a one-way rental from a touring-focused outfitter and confirm Spanish return policies in advance. Go in April–May or September–October; August heat and headwinds on the Spanish plateau make for a miserable final stretch.