Is paddle boarding good cardio?

Like any other exercise.......it depends on your weight, your fitness and the intensity of the workout.

According to this web site (and I have no idea how reliable their data is) it ranges from around 225 per hour for light paddling and goes up from there (http://www.surfinok.com/how-many-calories-does-paddle-boarding-burn/)

do you like doing it? then yes, it's good cardio.

This!!

I wore my hrm last week while I went paddle boarding and burned 277 calories in one hour. It also depends on age, weight and many other things.