Goalkeeper Andy Wilton, defenders Richard Halle and Ryan Sammons and midfielder Max Cornhill have all checked into the Len Salmon Stadium.
Wilton joins from Bowers` former league rivals Norwich United, who were relegated to the Thurlow Nunn League at the end of last season.
Despite suffering the drop, Wilton impressed in making 38 appearances for the Planters.
Before joining the Planters, Wilton had spells with Norwich City, Dereham Town and St Neots Town.
Sammons spent nine seasons with East Thurrock United, making 34 appearances last season in the Vanarama National League South, scoring 2 goals.
He made more than 400 appearances for the Rocks in total and represented England Schools under-18's before spending a year playing university football in the United States.
He joined the Rocks in 2008 and played an important part in the club’s rise through the Pyramid and also in the club’s historic FA Cup runs.
East Thurrock manager John Coventry told http://www.yourthurrock.com on his departure: “Ryan has been a tremendous servant to East Thurrock over the past ten years and played over 400 games which is a real credit to him. He has deservedly been a part of the clubs most successful period in its history.
“Ryan is a player that turns up for training and games and causes no problems always giving 100%. In my experience, as a manager of a non-League club that is a rare quality these days, especially when you know that financial reward is not his incentive and it is purely down to the love of the game.”
Cornhill is another former Rocks stalwart who returned to Rookery Hill last season after spells with Chelmsford City, Dartford and Concord Rangers.
He spent six years with East Thurrock in his first spell with the club.