No, we do not know where the ocean ends, because it essentially has no end.
As the reference states, defining the limits of the world oceans is difficult because there is no beginning and no end. The world's oceans are interconnected, forming a single, vast body of water. This interconnectedness makes it impossible to pinpoint a definitive "end" to any particular ocean. Instead, oceans transition into one another, blurring the lines between them.
