A jet ski has an average capacity weight limit of 400 lbs. Some models can carry 600 lbs.
A ski can carry 1-3 people, each model varies with hull design and engine. The weight limit is a total of people and gear. It is found on a sticker on the hull.
Sea-Doo 2 UP Spark max capacity 352 lbs
Kawasaki Ultra LX max capacity 496 lbs
Yamaha FX HO max capacity 530 lbs
Sea Doo GTX Limited max capacity 600 lbs
Here are some pictures of 2 people riding a jet ski: