Walenstadt has a population (as of ) of . , about 18.1% of the population was made up of foreign nationals. Of the foreign population, (), 73 are from Germany, 148 are from Italy, 400 are from ex-Yugoslavia, 24 are from Austria, 95 are from Turkey, and 107 are from another country. Over the last 10 years the population has grown at a rate of 6.8%. Most of the population () speaks German (88.5%), with Albanian being second most common ( 2.9%) and Italian being third ( 2.4%). Of the Swiss national languages (), 4,010 speak German, 22 people speak French, 110 people speak Italian, and 13 people speak Romansh.