If you're having a hard time finding a spot to lay your towel down on Waikiki Beach, try the following nearby beaches instead. 

San Souci Beach and the Natatorium (a War memorial) is located between the Waikiki Aquarium and the New Otani Hotel. There is a small parking lot for this beach. San Souci is a small beach and is a favorite kama'aina (locals) beach so it does get crowded on weekends. There are picnic tables fronting the beach, so its a great place to eat lunch or dinner. Get there early since the parking lot fills up. 

Diamond Head Beach, located near Diamond Head, is a good spot for windsurfing, surfing and sunbathing. There are hardly any people on this beach, so you will be able to find your own secluded area. Beach access is difficult as the mansions that line Diamond Head Road and Black Point have cut off public parking as much as possible. You can park at Diamond Head Lookout and scramble down the rocks or find street parking in the Black Point area (not easy). There are several lovely little beach parks on Diamond Head Road but again finding legal public parking nearby is very difficult. 

Kahala Beach (which is actually Wai'alae Beach Park) is a favorite beach for weddings and photo shoots. This is another beach that is rarely crowded on weekdays.  Locals and tourists alike use this beach due to the beauty as seen in this photo.  It is only 5 minutes from Waikiki by car, but a world away for a serene relaxing day on the beach.

Kahala Beach

Ala Moana Beach Park across the road from Ala Moana Shopping Center is another long stretch of beach that is a kama'aina favorite. There is lots of parking but there are also lots of people who go there to surf, paddle, jog or go to the beach. Go early to get a parking spot. This is another beach where you will see a lot of brides and photographers.

Kailua Beach Just over the mountain from Waikiki, lies the jewel of the windward coast, Kailua Beach. Suddenly the crowds of thousands shrinks to a minimal flow and turqoise water shines brilliant against the white sand beach. Most come here to go kayak to the Mokulua Islands, learn to windsurf or try their hand at Stand Up PaddlingIt will be difficult to return to Waikiki, after seeing what a real tropical beach should look like. View of Kailua Bay, Lanikai and the Mokulua Islands

 You can pick up beach chairs, umbrellas and towels at stores located all around Waikiki or you can save a little money and be enviromentaly friendly by renting beach gear.