Comillas is on the N-634 coastal road, about 43 km west of Santander. By car from Santander, take the A-8 motorway west and then follow signs south to Comillas; the drive takes about 45 minutes. From the west, the town is 35 km east of San Vicente de la Barquera.
There is no train station. ALSA buses run between Santander and Comillas several times daily, with journey times of around 90 minutes; connections are also possible from Torrelavega. The bus stop is on the main road at the entrance to town. A car makes exploring the broader coastline much easier, but Comillas itself is compact enough to manage on foot.