Hau Tree Beach, Waikiki

Hau Tree Beach, also called San Souci or Kaimana Beach, is one of my favorite swims in Waikiki! The water is clear and calm and the bottom is soft sand. Toddlers can play on the shore without waves scaring them. Best of all, there is a huge block of shade on the beach in the morning created by the high rises behind (shade is a rare thing on Waikiki Beach).

Behind the beach is a large grassy area with a zillion coconut palms- it's beautiful! Next to the beach is the historic natatorium, a 1920s hangout that was the "place to be seen."
A pretty Hau tree shades the lanai restaurant on the bottom floor of the Kaimana Beach Hotel behind the beach. There is a convenience store in the front of this hotel accessed from Kalalaua Ave where you can buy a yogurt or protein drink to take to the beach. You can have a drink at the bar in the gorgeous open-air lobby of Kaimana Beach Hotel, filled with local art and lanterns. They also have pastries and tea/coffee in their Hau Tree restaurant from 7-10am for about $6 each. The hotel has an amazing location between Kapiolani Park and Hau Tree Beach, but unfortunately the beds are old and uncomfortable.
Last time I swam here it smelled like sewer but I don't know if there is an outlet into the ocean here. It was also very crowded. 
Waikiki Aquarium is right by Hau Tree Beach and is a nice place to visit with your kids. The displays are excellent and the aquarium is small enough that it is easily do-able! There is a great Banyan tree where you can swing like tarzan between Hau Tree Beach and the aquarium- don't miss out on the fun! You can also see the fancy entrance to the historic swimming pool here, War Memorial Natatorium, sculpted in white. And walk directly on the water's edge on the Queen's Surf Boardwalk with crashing waves (behind the aquarium)- this is beautiful. It's lovely to come in the early morning and walk along this path behind the aquarium! Other local residents are taking long strolls and doing exercises on the grass. After a short walk, you come to Barefoot Beach Cafe, with its twinkling lights in a garden of trees, where you can eat fresh fish. I didn't like this cafe, even though many local couples return each week to eat there, because there are no restrooms, just public restrooms with homeless people camped out in them. They do have great live music though, Hawaiian music with beautiful harmonies. 
Kapiolani Park, a large, pretty park, is across Kalakaua Ave from Hau Tree Beach. Here you can see gorgeous views of Diamond Head. It's lovely to have a picnic here at the tables under the huge monkeypod trees. A popular 2-mile walk is to trace the edges of Kapiolani Park. Check out Queen Kapiolani Garden on the way, a small, free garden with tropical flowers on a busy street corner. 
You can walk east to Tonggs Beach where you will find a tiny wall and walkway by the sea, plus gingerbread-style houses, and then past Diamond Head Lighthouse to Diamond Head Overlooks for awesome, high-up, windy views over the water. Walk over to Monsarrat Ave for a row of cafes and coffee shops! Elks Lodge, steps away from Hau Tree Beach, is a place to eat with views of the clear water and reef below.

Directions

Park along Kalakaua Ave. The parking is metered and costs 25 cents per half hour, and it can fill up on weekends so come early. Bring quarters for the parking meters. There are showers at Hau Tree Beach, and restrooms at the nearby natatorium.
Click "satellite" and zoom in to see the natatorium and shady Hau Tree Beach from above.

Click on map for interactive view