It's the Law: Specifically for Skiing

Motorboat and PWC operators towing a person(s) on water skis or a similar device have additional laws they must follow.

Requirements for Towing Skiers

Every motorboat or PWC towing a person(s) on water skis, a wakeboard, or any other device other than a parasail must have either:
- A person on board, in addition to the operator, observing the towed person(s) at all times (preferably the observer is at least 12 years old) or ...
- An approved ski mirror that is at least three inches in height and eight inches in width, gives 180 degrees of vision behind the operator, and is designed as a ski mirror. The Missouri State Water Patrol does not recognize the manufacturer's mirrors on personal watercraft as being sufficient for this purpose.
Every motorboat or PWC towing a parasailer must have a person at least 12 years old on board, in addition to the operator, actively observing the parasailer.
Persons may be towed behind a motorboat or PWC on water skis, surfboard, parasail, or any other device only during daylight hours (sunrise to sunset).
A reasonable distance from other vessels, people, and property must be maintained so as not to endanger life or property. It is illegal to cause the person being towed to collide with any object or person.
An operator of a motorboat on waters of the Mississippi River, the Missouri River, or Missouri lakes between the hours of 11:00 a.m. and sunset must display a skier-down flag clearly whenever the towed person(s) is in the water. The flag should be lowered while the motorboat is engaged in towing but should be displayed again when the towed person enters the water.
In addition, it is strongly recommended that all persons being towed behind a motorboat or PWC on water skis or any other device wear a U.S. Coast Guard—approved PFD. Ski belts are not U.S. Coast Guard—approved.
It is against Missouri law to operate water skis, wake boards, or other such devices while intoxicated.