Tranmere have signed midfielder Robbie Weir and defender Michael Kay from Sunderland on one-year contracts.
Both were on-loan at Prenton Park last season with Weir, 22, making 18 appearances for Rovers.
Right-back Kay, 21, played 22 times, scoring one goal in the 4-0 win over Exeter City in April.
Tranmere have already agreed a deals to keep Andy Robinson and Adam McGurk at the club and have also completed a deal to re-sign defender Danny Holmes.
Tranmere manager Les Parry said: "Robbie Weir is a classy and versatile player who did really well here while on loan and his style of play suits the midfielders we already have at the club.
Parry continued: "Michael Kay settled into our back four very comfortably and showed he's more than capable of playing in League One. He's got an excellent attitude and has a bright future ahead of him."