beach, shore

(はまべ) A somewhat literary word for the beach
(はま) A very casual word for the beach, usually used by people who live on beach-towns.
(かいがん) The coast OR the beach! Unlike 浜辺 or  浜, 海岸 has a scientific, geographical meaning:the coastline, (regardless of if there’s sand or not). You’ll see 海岸 on maps. The usage of 海岸 is odd, even for Japanese. Where Americans will just say, “Let’s go to the beach!”, Japanese might suggest to their pals, “海へ行こう!”(let’s go to the ocean!) but ONLY ONCE THEY WERE ALREADY THERE, then they might specifically suggest going to the 海岸 – as opposed to other things to do by the sea. Weird!    $$$
(きし) The shore. Unlike 海岸 or 浜, you can use 岸 for the shore of rivers or lakes, as well as the ocean.