Santurce-Antiguo has a population of approximately 45,000 residents. The town is known for its strong Basque identity, with a majority of the population speaking both Spanish and Euskara, the Basque language. The population is diverse in terms of age, with a mix of families, working professionals, and retirees calling the town home.
In recent years, Santurce-Antiguo has experienced moderate population growth, partly due to its increasing popularity as a residential area for people working in nearby Bilbao. The town also sees an influx of tourists during the summer months and festival seasons, adding to its vibrant and lively atmosphere.