10 July 1989 — Pau to Cauterets, The first mountain stage of the Tour departed south-west from Pau, through
Lasseube to
Oloron-Sainte-Marie. The riders then headed south through
Gurmençon to
Escot, to begin the climb east to the Category 1
Col de Marie-Blanque to . The route then descended east to the valley floor at
Bielle, before beginning a gentle climb south through
Laruns and turning east to
Eaux-Bonnes. The riders then began the
Hors catégorie climb of the
Col d'Aubisque to , partially descending through the
Col du Soulor, and then climbing the Category 2
Col des Bordères to , before the final big descent to
Argelès-Gazost. Heading south, the brief climb of the Category 4
Côte de Saint-Savin was followed by a quick descent to
Pierrefitte-Nestalas. The race continued south, beginning the ascent of the Category 1 climb to Le Cambasque, west above Cauterets, at an altitude of . ==Stage 10==