Stevenage have signed defenders Ronnie Henry and Simon Walton and midfielder Chris Whelpdale as free agents.
Henry, 30, returns to Boro after two years at Luton Town, whom he opted to leave this summer after skippering them to the Conference Premier title.
Winger Whelpdale, 27, turned down a new deal at Gillingham, where he played 108 league games in nearly four years.
Walton's two-year spell at Hartlepool came to an end in May when the 26-year-old was released.
The versatile player, who started his career at Leeds and has also made moves to Charlton, QPR and Plymouth, will miss the League Two season opener against his former side as he still has two games remaining on a four-match ban.
Henry played under Stevenage boss Graham Westley during his first spell at Broadhall Way, when he helped the side achieve back-to-back promotions from the Conference Premier to League One in 2010 and 2011.
The club have not released the length of the deals.