Swimming is possible in the Kipahulu Area (coastal) of the park - but only when conditions allow. The freshwater pools at `Ohe`o Gulch are prone to very dangerous flash floods, and injuries and deaths have occurred.
Always check at the visitor center for current conditions before entering the water, obey all posted signs, and use your best judgement.
Remember that Kipahulu is a natural area, where you are responsible for your own safety.