The 32-year-old, who made 28 appearances for the Cherries last season, signs a one year deal at the Priestfield Stadium.
After his first season at the Goldsands Stadium was cut short by a hamstring injury, Barrett featured in four pre-season friendlies this summer.
New signings Miles Addison and Tommy Elphick will compete with Stephane Zubar and Steve Cook for a place in manager Paul Groves’ starting line-up.
Everyone at AFC Bournemouth would like to thank Adam for his efforts over the last 12 months and wish him good luck for the future.