Is a seatbelt ticket a moving violation in ca?

It depends. Were you MOVING when you were stopped? Generally, a MOVING violation means the car was in motion when the violation was noted and/or recorded. In California, of course, they could decide that having your car in a garage is a moving violation. Ask the guy who wrote the ticket. I don't think most cops will come up to a car that's not moving and say "Hey, jerk, fasten that seatbelt..." - He'd just wait until you started to drive away and then nail you.