The 22-year-old has put pen-to-paper on a two-year contract at the Jakemans Community Stadium after leaving Bloomfield Road at the end of last season.
Lankshear began his career in the non-league game with St Albans City and has enjoyed loan spells with Dorking Wanderers, Welling United and Ebbsfleet United during his time at Blackpool.
He reported for pre-season training on Thursday morning, as the Pilgrims’ preparations for the new National League campaign began in earnest.
Lankshear, whose younger brother Will plays as a striker for Tottenham Hotspur, is Graham Coughlan’s 10th new signing of the summer.