Ellen Packham, Emma Wallis and Rachel Hindle are the newest additions to the MFC Women team.
Defenders Ellen Packham and Emma Wallis both join Boro from Newcastle United after helping the Magpies win the National League Division One North title last season.
Experienced defender Rachel Hindle arrives on Teesside from Leeds United, where she made 22 appearances last season.
The three new additions take the signing total up to six so far this summer for MFC Women, following the recent announcements of Abby Towers, Sarah Burn and Beth Guy.