"This is a humane gesture on the 25th anniversary of king's reign, annulling prison sentences, while maintaining the rights of the victims," the source said.
The Moroccan constitution gives the right to the king to pardon or commute sentences, a decision usually taken on national days.
The three journalists were outspoken critics of public policies and had all been convicted on charges including sexual assault, which they denied.
Human rights defenders had denounced their trials as politically motivated.
Editor in chief Taoufiq Boachrine was sentenced to 12 years in jail in 2018, Omar Radi and Soulaimane Raisouni were both sentenced in 2021 to 6 years and 5 years respectively.
The King also pardoned 16 inmates convicted on extremism and terrorism charges "after they reviewed their positions," Morocco's justice ministry said.y
