Find out about diving flags, lights, signals and other important diving information.

  Diving lights

Diving light
Diving light

People involved in night diving without a vessel are now required to display a yellow (orange) flashing light that can be seen from a minimum distance of 200 metres.

At night time a boat must show the International lights to indicate that a vessel is restricted in her ability to manoeuvre. These are three lights in a vertical line, the top and bottom are red and the middle one is white.

The diver's boat should also show other appropriate lights such as an anchor light.

Diving operation boat lights and flag
Diving operation boat lights and flag

  Diving flag

All vessels are required to display a flag of size 6 of the International Flag Code or not less than 750 mm in length and not less than 600 mm in width.

International code flag A
International code flag A

Diving from a boat

Any boat with divers operating from it must always display signals by day or night to inform other boat users.

The daytime signal for divers is an International Code Flag A. The flag must be at least 750 mm long and 600 mm wide.

Divers operating without a vessel must also display the International code flag A.

The flag may be displayed from a jetty (for example) and must be at least 750 mm long and 600 mm wide.

Exception to size: If displayed from a buoy, the flag must not be less than 300 mm in length and 200 mm in width.

The flag must be clearly visible to all vessels operating in the vicinity.

  Boating safety for divers


Before you depart from home:

  • Leave a detailed copy of your plan for the day with a responsible friend. Be sure to tell them what time you are expected to return home.
  • As soon as you are clear of the ramp, call your local Sea Rescue Group to test your radio and remember to log in with them before you venture out of the harbour.
  • Always log off when you return to avoid an unnecessary search for you and your boat.

Volunteer Sea Rescue Groups are there for your safety. If you are unsure of who or how to do the above, contact the Department or the Sea Rescue Group in your local area.

Anchor and line

Always check and ensure that your anchor and chain are in extremely good condition. The size of the line and chain, and the type and weight of your anchor should suit your particular boat as well as the type of bottom you intend to anchor in.

Ensure you have:

  • Plenty of line to suit the depths of water that you normally anchor in (at least 3 to 5 times the depth of water).
  • Allowed extra line for surge, tide and increased wind.
  • Moused the shackles (use a piece of wire to prevent the pin from coming undone and falling out).

When you enter the water, swim down and check that your anchor is firmly embedded and that your anchor line is not likely to snag on a reef outcrop that may cause it to chafe through.

Weather checks

Get an up-to-date weather forecast before you go. Sea Rescue Groups also offer up-to-date weather forecasts for the area you are operating in. Have contingency plans for bad weather.

During a one hour dive things on the surface can deteriorate rapidly with the arrival of the sea breeze.

Unattended boats

The practice of divers leaving vessels unattended is very dangerous. The potential for disaster is real when vessels are left unattended by divers.

It is strongly recommended that a responsible person stays onboard your boat at all times whenever divers are below.

This designated person may be required to:

  • Raise an alarm if the diver is overdue to surface.
  • Attend to the vessel should it start drifting.
  • Assist divers back onboard after the dive.
Opens in a new window Volunteer Marine Rescue Western Australia

  Operating vessels near divers

All boats must keep at least 50 metres clear of boats, buoys or areas showing diving signals.

Where this is not possible, the approaching vessel should:

  • Proceed at the slowest speed at which the vessel can be safely navigated.
  • Maintain a proper lookout for persons in the water.


Diver below sticker
Diver below sticker

The following sticker is available from Marine Safety.

For a copy of the Caution! - Diver below sticker email us or call 13 11 56.

Image of diver

Page last updated: Thu Jul 4 2019 8:47:31 AM