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It's the Law

Other Equipment and Regulations

Diver-Down Flags

State law requires that scuba divers or snorkelers display the diver-down flag to mark the diving area. Divers must stay within a 50-yard radius of the flag. Vessel operators must not operate within 50 yards of a displayed diver-down flag. Two types of flags indicate diving activity.

Divers Flag

A rectangular red flag, at least 12 inches x 16 inches, with a two-inch white diagonal stripe is required on Missouri state waters.

Alfa Flag

A blue-and-white International Code Flag A (or Alfa flag) is required on federally controlled waters.

Divers and Alfa flags
Divers and Alfa flags

Skier-Down Flags

Skier flag
A rectangular red or bright orange flag, at least 12 inches x 12 inches

A flag indicating a “skier down/person in the water” is required equipment for a motorboat (other than a PWC) towing a person behind on water skis, inner tubes, sleds, or similar devices. This flag is to be displayed when the person is in the water before or after being towed on water skis or similar devices or when a swimmer leaves the confines of the vessel. Displaying the flag is required from 11:00 a.m. to sunset and is in effect only on the Mississippi River, Missouri River, and the lakes of this state.

The color of the flag must be either red or bright orange.

The flag must be square in design and measure at least 12 inches on each side.

When displayed, the flag must be visible for 360 degrees.

All vessel operators in the vicinity of a displayed skier-down flag are required to operate at idle speed if closer than 50 yards to the vessel displaying the flag. It is suggested, when operating in the vicinity of a displayed skier-down flag, that operators immediately start scanning the water for the downed skier.

All vessel operators are encouraged to maneuver away from the area in which a skier-down flag is being displayed.

This flag is to be displayed only when the skier (or person being towed on inner tubes, sleds, etc.) is in the water before or after being towed. Once the skier is up and being towed, the flag must be lowered. The flag must be raised again when the skier falls or stops skiing and enters the water in order to return to the motorboat.

PWC and moored or anchored motorboats are exempt from displaying the skier-down flag.

Use of Fireworks

State law prohibits the igniting or discharge of fireworks by persons on board vessels, except in the case where a display permit has been issued.

Also, persons may not throw or place any ignited fireworks into a vessel or near any other person. This prohibition does not include the proper use of pyrotechnic visual distress signals.


Dock owners on Missouri lakes managed by the United States Army Corps of Engineers and on Lake of the Ozarks must post an emergency address on the dock. The address should be posted on the lake side of the dock facing the water using a minimum of three-inch lettering. The address should give a street address or emergency 911 address closest to the dock along with a zip code. The intent of this law is to aid in the location of and reduce the response times for emergency and non-emergency calls on the water.