You may run across boats engaged in diving operations almost anywhere, so keep a sharp lookout and scan the water ahead of you.
Boats engaged in diving should show a rigid replica of the internationally recognized "Alpha Flag". This is a blue and white flag with a swallow tail. Additionally, the traditionally used "Divers Down" flag should be flown from the boat or from a float over the divers. This red flag with a diagonal white stripe should be easily seen on the water.
If you spot either or both of these flags, keep well clear (at least 100 to 200 feet depending upon state law) from the vessel and diver down flag, if floating. Also watch carefully for bubbles breaking the surface. It could indicate that a diver has strayed from the area and may not be near the dive boat.