One thing to watch out for during the swim in open waters is the organic life hazards like Jelly Fish (the most common), Portuguese Man Of War (not so much), a shark (rare), and salt water crocodiles (low probability) hence I prefer to use my scuba diving face mask because it gives a much wider and clearer view compared to a swimming goggles.
Other non-organic hazards are fishing nets, boats, and sharp objects that are submerged.
Strong currents are common in my place particularly the rip currents and have taken many lives yearly but is not really a threat for me.