Castro Urdiales lets you go with the sea still at your back, and then the hard work begins. The path climbs and descends all day. Hill after hill, never long enough to find a proper rhythm. Almost 600 metres of climbing, spread over a long day.
So pace yourself. Start gently, take breaks more often than you think you need to and eat before you get hungry. Allow around 9 hours on your feet. At the end, Laredo awaits, with a broad sandy beach and an old town centre. That’s a fine reward for tired legs. You’ll get there one step at a time, and Laredo isn’t going anywhere.