The information on this page comes from Kauai's Beach Safety Guide, and is supplemented with commentary from the Ultimate Guidebook – Kauai Revealed, and our own experience. 

ALL BEACHES IN HAWAII ARE PUBLIC (EXCEPT THOSE BY THE MILITARY BASES)

Hawaii & the Pacific Ocean in the Winter:  For those who have not been out there, the Pacific (especially around the islands) is a very different creature than the Atlantic Ocean.  First of all it is much warmer, and for the most part, much smoother and cleaner.  Winter swells can come quickly on an ocean that looks reasonably peaceful moments before – this especially is true on the NORTH SHORES of all the Hawaiian Islands.  Where the space between the open ocean and shore is broken by extensive coral reefs, the effects of such swells are mitigated a bit. 

Maui Beach Note: The Waimea and Ka'anapali beaches tend to be the safest on the island because they are on the protected side, and anything big coming towards them first hits (and gets slowed down by) Lanai, Molokai & Molikini Crater.  Waimea is great for SCUBA diving & snorkeling (you can see some great things 15-40 feet down, so you always know where up is), and Molokini Crater is spectacular (as long as you don't mind the sharks).

Oahu Beach Note: Waikiki Beach is a bit cheesy, but is a tradition, and is not as bad as Ocean City, Atlantic City, or Coney Island.  In fact, the vista is amazing and you have to at least set foot there because it is part of the Hawaii experience.  This beach is very protected and is one of the safest in Hawaii -- it also is a great place to learn how to surf because the waves are very gentle.  Additionally, the crowded beach is offset by the fact it is adjacent to a street containing some of the world's best shopping (OK, NYCers won't be awed).

KAUAI BEACH GUIDE

Safest Beaches for Swimming (READ - OK for Kids to Swim)

Lifeguards are on duty on the following Kauai beaches:

 North Shore– Pine Trees Beach & Hanalei Beach Park

 East Shore – Anahola Beach Park, Wailua Beach & Lydgate Park

 South Shore – Poipu Beach Bark

Sometimes there also are lifeguards at Ke'e and Wai'oli

Best Snorkeling, SNUBA & SCUBA Diving

The Concierge at the Princeville can help set you up with one of the better outfitters on the island if you want a guided trip.  The hotel offers its guests free snorkel, goggle & fin rental.  Always go with a buddy.  If you are planning on surfing or going far out into the ocean without a guide who knows the area, spend about 20 min. watching the ocean, tides, waves & currents before you go out.  Turtles and a large variety of fish are very common around Kauai.  The island has lava tubes, reef ledges, and many good diving walls.

Snorkeling:

BEGINNERS:

– Lygate State Park in Wailua has an area protected by a ring of boulders.  Morning is best.

– Princeville has great snorkeling for beginners -- there is a large variety of colorful

   fish although the coral is not as spectacular as elsewhere.

INTERMEDIATE:

– Ke'e and Tunnels are great during CALM weather, as is Hideaways beach

– Po'ipu Beach Park

SNUBA:

Snuba is similar to SCUBA diving, but you are connected to an air tank on a raft above you.  This obviously limits your mobility a bit, but allows you to go down 20 feet.

SCUBA:

BEGINNER LESSONS:

– Ocean Quest is highly recommended for introductory SCUBA.

GUIDED DIVES FOR CERTIFIED DIVERS:

– For shore dives, Ocean Quest

– For boat dives, Bubbles Below & Fathom Five

BEACHES:

–  Ke'e Beach (North Shore, good on calm days, area near reef drop-off is good)

–  Tunnels (North Shore, good on calm days, easy access, turtles, reef sharks, lava tubes, caves -- go w/ a guide)

–  Cannons is a second choice to Tunnels and has similar qualities (North Shore, good on calm days, roadside access)

–  The Hole (North Shore, good on calm days, off the Princeville)

–  Kahala Point (East Shore, entry/exit is a pain, but lots of fish & good reef)

–  Koloa Landing (South Shore, easy entry, usually calm, decent coral - best at high tide)

–  There are more advanced dives available off Ni'ihau w/ tons of larger sea life

Best Surfing Beaches

If you are planning on surfing or going far out into the ocean, spend about 20 min. watching the ocean, tides, waves & currents before you go out.

– Ha'ena (Cannons -- in calm weather, for experienced surfers)

– Tunnels (experienced surfers)

– Pu'u Poa (experts only)

– TO BE CONTINUED . . .

Prettiest Beaches

– Lumaha'i (from South Pacific, part of Hanalei Bay – picture perfect – do not swim here, EVER)

Good Sunning, Swimming & Wading

NORTH SHORE:

–  Ke'e Beach (a favorite, stay away from far left side where reef breaks)

–  Ha'ena Beach (good facilities, located across from the Dry Cave, stay away from Cannons beach on the left side, don't let kids go more than a few feet out)

–  Kahalahala Beach (next to Lumha'i, but protected -- a TIDE POOL for kids to play in -- while supervised)

–  Hideaways (Pali Ke Kua - not after a rain)

–  Queen's Bath (at low tide, not after a rain)

–  'Anini Beach (one of the safest on the North Shore, very shallow water

–  TO BE CONTINUED . . .

Best Sunsets

–  Poli Hale -- Barking Sands

RIP Tides

First and foremost do not panic.  Panic is exhausting and not particularly useful.  DO NOT FIGHT THE CURRENT.  SWIM PERPENDICULARLY to the direction the current is taking you.  Wait until the current releases you -- it will.  Swim parallel to the shore and make your way in. 

RIP currents are caused by large waves that cause water to surge over shallow reefs.  Near the shore, the volume water of water collects and moves along the shore until it finds a deep opening/break in the reef.  The water returns to the ocean through this deeper opening.  Feeder currents come together at these openings and become the "head" of the RIP current –– the head rapidly moves away from the beach and dissipates once it gets back to the deeper ocean.