It helps to zoom in when clicking potential landing zones.

I did a (boring) 100% planetary survey and one of the fauna I needed to scan were fish in the water close to the shore. I spent wayyy too much time running around looking for water until I realized there was always some within a couple hundred metres of the ship landing site (I assume it’s generated that way for that biome type).

When you’re landing on a Whatever (Coast), keep your eyes open to see what direction the water is when you come in. Otherwise it can be hard to see it from the ground if it’s a foggy world.