If a monk chooses at level 1 to use his fists does he get to make 3 attacks, assuming he uses his bonus action?

  1. Right Fist: 1d4 (unarmed strike) + dex
  2. Left Fist: 1d4 + no mod for second weapon
  3. Bonus Attack Unarmed Strike: 1d4 + Dex

They'd get 2 attacks.

TWF uses the bonus action you want to use for the third attack. The monk's martial arts feature also uses this bonus action. So it would be:

  • Action: Left Fist (d4+dex)
  • Bonus Action: Right Fist* (d4+dex) from Martial arts

This allows you to make 2 full attacks instead of just the attack from the bonus action (that wouldn't otherwise be possible without martial arts because unarmed strikes are not typically light).

*this does not have to be a different weapon, it can be the same fist, a punch or a headbutt or whatever. unarmed attacks are free to be given the flavor you want to give them.

