Im interested in the correct legislation answer for this too.. I dont believe there is an age limit as long as they have the appropriate pfd and i doubt anyone would really want to take their under 12month old on a ski anyway.. How many? Kids between 1yr an 12yrs an classed as 1/2 person in all the wording in the info online as a BOAT carrying capacity,I cant find anything regarding pwc's -
Going off the info on the label itself it is the same as boats.
Ie: applies to dinghies, open runabouts, motor boats, half cabins and jet skis.
Warning .3 children up to one year should not be counted for loading purposes. Children between one year and twelve years can be counted as 1/2 of an adult.
http://www.msq.qld.gov.au/Safety/Capacity-labels.aspx
http://www.msq.qld.gov.au/~/media/ms..._equipment.pdf