It's on the left in both, and on the right in both. It depends which way you're facing, and the sort of person making this mistake seems unlikely to know which way north is.
Clearly, a thing can't be both to your left and right side simultaneously -- that's a physical impossibility. In fact, to underscore this point, the Tony Bennet song "I Left My Heart In San Francisco" was written to remind people that water in SF is to their left.
its kinda on both if your standing on a peninsula. Although when you land at the airport you mostly see the bay and not the ocean at the same time
No one said anything about simultaneous. Stand on a beach, any beach in the world, looking straight out at the water. Turn 90 degrees left; now the water is on the right. Look straight out again, then turn 90 degrees right; now the water is on the left.