Things we know about Flidais from Irish mythology:
- her epithet is Foltchaoin "soft haired"
- she has 4 daughters according to the Lebor Gabala Erenn: Arden, Dinand, Bé Chuille, and Bé Teite
- Fand is also her daughter according to the Metrical Dindshenchas
- her son is Nia Segamain according to the Banshenchus which also says her husband's name was Adammair
"Flidaise Foltcháin, that is, Flidais the queen, one of the Tuath Dé Danann, 'tis she was wife of Adammair son of Fer Cuirp; and from her Buar Flidaise ('Flidais's cattle') is said,
Nia Ségamain, that is, ség 'deer' is a máin 'his treasure'; for during his time cows and does were milked in the same way every day, so to him beyond the other monarchs great was the treasure of these things. And it is that Flidais (above-named) who was mother of Nia Ségamain son of Adammair; and in Nia Ségamain's reign those cattle were milked, that is, double cattle, cows and does, were milked in the time of Nia Ségamain, and it was his mother that gave him that fairy power."
- she possesses a magical cow which can feed 300 men in a single milking or an entire army in a week (Táin Bó Cúailgne and Táin Bó Flidais)
- according to the Banshenchus: "Though slender she destroyed young men. She decreed hard close fighting."
- in the Táin Bó Flidais she was the lover of Fergus mac Roich, who otherwise needed 7 women to satisfy him