Good cycle lanes from Bayonne to Anglet, despite being a little narrow, even out of season. Shared lanes while crossing Biarritz. In Biarritz, bicycles and cyclists aren’t well catered for, hence the one-way system along the shoreline... If you are following the Vélodyssée from south to north, do this loop anyway. There are several hills to contend with.
The connection towards Biarritz station is on a steep incline.