This hat is ultralight, crushable, breathes well, and keeps the sun off round the head. I’ve had a hemp Caribe hat from Watership Trading Companie for about four years and I don’t go out in the sun without it. It is much lighter than any other hat I’ve seen with a full brim.
When I’m kayaking I periodically dip it in the water. The off-white hemp dries faster than cotton canvas, doesn’t have a leather band to bleed color or get sweaty, and always looks good.
The Tilley hat you recommend already is a great hat too, and I notice it now comes in hemp. But it isn’t as simple and light as the Watership hat. (I wish the manufacturers listed the weights of all their hats.) If the strap were cut off (and if you can get one to fit as well as mine, the strap is unnecessary) the Watership hat would be essentially rotationally symmetric while the Tilley has a narrower brim on the sides, and is generally narrower all around. The Tilley hat seems designed to have a vented airspace above the head (and is thus stiff enough to stay erect) while my hat fits snug on top of my head.
Lastly, the Watership is $13 cheaper. Made in the US (my hometown of Bellingham, WA), from sustainably grown materials, I can’t recommend the hemp Caribe hat enough.