[AliVeritas]

Thank the Lord. Can we say the St. Michael's prayer after Mass as well?

[NYer]

Absolutely!

[A.A. Cunningham]

We can say it anytime.

Saint Michael the Archangel,
defend us in battle.
Be our protection against the wickedness and snares of the devil.
May God rebuke him, we humbly pray;
and do Thou, O Prince of the Heavenly Host -
by the Divine Power of God -
cast into hell, satan and all the evil spirits,
who roam throughout the world seeking the ruin of souls.

Amen.