The Rocks have struggled down the bottom in the first seven weeks of the new season.
The National League South club have added forward Batt, who moves across Essex to join John Coventry’s team.
Batt didn’t quite get the game time he wanted at Chelmsford City and was released by Rod Stringer on Thursday.
East Thurrock are third from bottom and have just six points from their first ten matches.
Their next league assignment is a game with Wealdstone on September 29.