Beach Safety Tip #1: Choose a beach with a lifeguard
      It is best to swim at guarded beaches. But keep in mind that lifeguards are 
      
      humans too and they can't watch everyone all the time. Stay within sight and 
      
      near the shore.
Beach Safety Tip #2: Pay attention to beach warning signs
      Whenever possible, signs are posted on beaches that warn beachgoers about current 
      
      dangers, such as strong currents, stinging jellyfish, sharp corals, slippery 
      
      rocks and other hazards.
Beach Safety Tip #3: Don't swim at remote beaches
      If you want to swim at a remote beach and notice that no one else is in the 
      
      water, stay out. There is probably a reason why.
Beach Safety Tip #4: Never turn your back on the ocean
      Sudden large waves can sneak up on you and sweep you off the beach or rocks 
      
      and pull you out to deep water without warning.
Beach Safety Tip #5: If in doubt, don't go out!
      Whenever you're not sure if a beach is safe to swim at, don't enter the ocean. 
Rip Currents

Here are some safety precautions that you can take:
What to do if you find yourself in a rip current:
If you see someone caught in a current, don't become a victim too:
Final Tip: The individual beach conditions on all Hawaiian islands are seasonal, meaning that in some months a particular beach can be great for ocean activities, such as swimming, snorkeling, surfing, etc. but in other months these activities may not be possible or may even be hazardous. Always check with the lifeguards before going in the water and use common sense. And remember: "If in doubt, don't go out."