How much do 2 jet ski's on traler weight?

It depends on the model of jet ski and the type of trailer. Larger jet skis weigh more than smaller ones. Steel trailers weight more than aluminum ones. It also depends how much gear and fuel you carry on the trailer.

A good range would be 600 pounds (two small, one-person jet skis, aluminum trailer, no gear) to 2,200 pounds (two large, three-person jet skis, steel trailer, four full fuel jugs, tools, spare tire, and so on).