The first place I would look is the tub waste and overflow. Most leaks happen there, and they are the easiest to fix. If you have water below the jets and it's leaking, then it may be the shoe. It could also be on the water supply to the tub spout, or in some cases water getting past the overflow if that is loose or improperly seald. There will be a rubber seal that clamps between tub and overflow.
If you raise the water above the jets, then depending on overflow style, could be at a higher slipjoint connection.
Also the jet piping becomes a consideration.
Does this have a hand spray? Once more source for a leak. Even if it's just water running back down the hose when using it.