The choices are many, Wide brim hats like an Akubra, soft cotton bucket hats or baseball style hats. They are all good functional fishing hats that do the job of giving you sood sun protection and sheding water when it rains. Coming from a cattle farming background I wore an Akubra for decades and still have a couple in my wardrobe, the wide brim definitely give you plenty of protection from the sun and nothing sheds water like the Akubra so a good choice for a fishing hatm if the size fits. The bucket hat made of soft cotton is comfortable and protects from the sun and keeps you dry in light rain but they don't have a good peak to shade your eyes from the sun this is important when polaroiding for fish but still a good fishing hats if you prefer them. The base ball cap style I find the best it's light comfortable protects your head and eyes from the sun and offers some protection in light rain. It's major draw back is it offers no sun protection for your ears, as I always wear a neck sock to protect me from the sun and reflection from the water I have no problem with these fishing hats and as they are adjustable the size fits. Be sure that the underside of the peak on your fishing hat is black or a dark colour to minimise reflection from the water. This is very important when polarioding for fish.
Head socks are a must no matter what style of fishing hast you wear.
So do your homework and choose wisely.