The rise surprised analysts who had predicted that it will remain flat in September.
Meanwhile, in the EU the indicator rose to 105.6 points from 103.8 points in August.
In Latvia ESI increased to 104.7 points compared to 103.1 points a month ago. Data about Latvia suggest that consumers confidence has risen in all surveyed areas.
Meanwhile, in Estonia the indicator rose from 101.3 points to 102.9 points, and in Lithuania it grew from 106 points to 107 points.