what is best sun cap/hat protection during wsurfing?

I use a Dakine hat. It does the job and is waterproof, reasonably comfortable too. There are others out there. Some use a plain old cap so it comes down to personal preference. I like the ones with a chin strap so it does not blow away. Some hats probably have zip pockets for keys wallett and phone, but do you really need it? I did hear of a guy whose hat blew off during a fast run. He turned downwind to retrieve it but failed to see the sandbank between him and the floating hat.

Surf hats with a stiff front brim and removeable legionnaires flap are very good. Dakine, O&E make them.

FCS do a good bucket hat with a stiff brim
if you prefer a cap, I got an Ocean and Earth mesh Truckers Surf cap, which has a strap. I've been happy with that too

+1 for O+E bucket hat. Keeps my glasses from flying off mid catapult.

I have a RipCurl bucket hat. It's much the same as the FCS, Indo, etc with a neoprene chin strap for stretchy comfort. I had to add a strap around the back of my head to stop it falling off whenever my head went under. A shoelace through the vent holes and over the top did the trick.

FK H 2 O hat - stays on, great protection, lasting well so far

I liked and wore the FCS bucket hat for 4 seasons. I now wear the Garth helmet my wife bought me for Christmas.

Gath helmet peak or full face visor best way to keep the sun off windsurfing.

A helmet that covers the ears and has a peak to shade the face. .

Add a neck shade tail where nessasary, but is generally less needed as the back of the neck is generally shaded a bit by the body leaning back.

My biggest concern is is sun exposure on the ears, I've been surprised at the number of people I know who have had bits taken off them to remove spots that were turning nasty. As a result I wear a helmet that covers my ears almost all the time, although will wear a Tilley hat in light conditions. Tilley hat has a small amount of closed cell foam in the crown so will float if it comes off in a fall

Good point point Pacey. My ears are getting a bit munted, my cap's not the best for that. Might have to go back to the bucket hat. I removed the ear covers from my Gath as I didn't like the wind noise

Above 20 knots the front blows up. Below 20 it stays down.

The solution is to wear a rigid cap underneath and the windsurfing hat on top - perfect.

After 30years of windsurfing and a squamous cell carcinoma cut off from top of my head few years ago,
I always wear a helmet now. Besides the sun, it also keeps me warm in winter and offers protection from the
occasional knock from the mast. Now that I've started foiling, it's essential.

Surf Logic make a good bucket hat with a stiff brim and chin strap.

I never seem to find a helmet to fit my very narrow, long head. I'm just too perfect aerodynamically .
Hats of all sorts tend to fly away in strong winds, so in light wind I wear an ordinary baseball cap and once it's blowing I swap it for a Gun Sails neoprene beanie, which has a cord to fix it to the wetsuit zipper. Generally it sits rather tight on a short crew cut, which I'm left with as the only possible option due to an extremely receding hairline . It tends to fly off in forward loop rotations, though. Hence the cord comes in handy.

I have a Neil Pryde one I like I wear it for kids nippers Suping etc but windsurfing I wear a helmet. It has a neck flap that can be removed.
www.scboardsports.com.au/collections/hoods-surf-hats/products/2018-np-surf-bucket-hat