What you wear to the beach in Hawaii and what you wear to the beach in Japan are quite different.
In the Japan the ocean water is cold for most of the year, so you'll need to wear a wetsuit.
But during winter months, you will also need.
Gloves
Boots
Head cap
In Hawaii, the water is warm. All you need is your board shorts ( or bikini if you're a girl ).
In the Spring and Fall in Japan, we can wear thinner 3mm wetsuits
But in winter, you need smooth skin 5mm or maybe even dry suits.
Most of the year in Hawaii, you don't need more than your board shorts. But Dawn patrol and Sunset surfers might wear a thin 1mm long sleeve top, like the one I'm wearing here.
But in Japan, not only do you need your wetsuit, you'll also need:
#1 Bucket to put your soaking wet wetsuit into for the ride back.
#2 Hotwater container to rinse yourself off after surfing.
#3 Neoprene lined carrybag for that hotwater container.
#4 Changing mat to stand on when getting out of your wetsuit ( some people use an EVA bath mat or ever astroturf ).
#5 Wide shoulder hanger to hang your wetsuit up if your intend to surf two rounds.
#6 Not neccessary, but some surfers use a small plastic shopping bag to insert their foot into to help slide into the wetsuit leg.
Then after you get home you got to rinse out the wetsuit in a bucket ( or in the bath tub ) Japan doesn't have those big outside sinks/basins like in the U.S. Some people also put fabric softener. Then you got to let it dry inside out for a day, then flip it right way out, then dry for another few days.
You need to take of your wetsuits, since they cost sometimes $600 - $1000 for a normal wetsuit.
( and Dry suits cost even more ! )
In Hawaii, just put on your board shorts, drive down to the beach, surf and drive back home, still in the same board shorts.
Do you know you can't drive to the beach in Japan just wearing board shorts ?
By Law, you need to be wearing a t-shirt or something that covers up your top while operating a vehicle.
Surfing in Hawaii is way less complicated than surfng in Japan.