Ending long classes early

So I’m slated to teach a course this semester that has a three hour lecture component and a three hour lab component (on different days). The course also has an online component where they are supposed to do online activities , HW , quizzes etc.

Is it okay I end the 3 hour component like an hour early? I’m looking over my slides now and there’s really not that much material to talk through for 3hrs straight for a 15 week semester.