Date of birth
Moore became joined Blues at the start of the 2018/19 campaign from Championship side Bristol City and will stay with Southend for the whole season.
The defender, who is capable of playing anywhere across the backline, signed for Bristol City in the 2016 summer transfer window on a three-year contract from French side RC Lens for a reported seven-figure fee.
Moore played seven games in all competitions before signing for Bury on loan in January 2017, which saw him make 19 appearances for the Shakers and concluded against Blues on the final day of the 2016/17 season.
A year ago Moore joined League Two Cheltenham Town on loan for the duration of the campaign and totalled 39 games for the Robins.
Moore was assigned shirt number 23 for season.