How long is a day on Charon?

About 153.3 Earth hours · orbits Pluto every 6.4 days

The only moon that has mutually locked its planet - Pluto and Charon forever show the same face to each other

Charon is so massive compared to Pluto that they BOTH are tidally locked to each other! From Charon, Pluto never moves in the sky. From Pluto, Charon never moves. They're frozen dance partners, locked eye-to-eye for eternity!