It is quite easy to get to Zarautz by different means of transport from the capital of Gipuzkoa province, San Sebastian.
By train
By train
There is a frequent train, Euskotren (http://www.euskotren.esusually) every 30 minutes, which departs from San Sebastian. Note that this is not the same as the Renfe service which connects San Sebastian with major cities in Spain and France. You need to go to a different station altogether. The journey to Zarautz takes 30 minutes.
By bus
By bus
The Euskotren company also runs buses every hour to Zarautz from San Sebastian. There other buses in summer which arrive in Zarautz from Pamplona.
By car
By car
It takes 15 mins by car to arrive to Zarautz from San Sebastian by the highway A-8; which connects San Sebastian and Bilbao.