China Walls is another name for an area overlooking Portluck Point on the Southeastern point of O'ahu. As you're driving toward Hanauma Bay, Sandy's Beach, and Dragon's Nostrils, you'll pass Hawai'i Kai, a fairly affluent area of Honolulu. When you get to the Foodland, turn right on Lunalilio Rd and then turn right on Portluck Rd. Park anywhere around there and walk down the hill. You'll see people hanging down on the rocks/cliff. This place has one of the best views in the city for sunset and most travel books don't even talk about it. The sun sets right over Diamond Head. You won't see signs for it, either, but locals know it as a great place for surfing and cliff jumping.
This is not a beach. It is just a cliff wall where you can jump into the water, watch surfers, and watch the sunset. China Walls is infamous both for its breathtaking beauty as well as treacherous waters. Due to the numerous fatalities that have taken place over the years, China Walls has gained the reputation of being unpredictable and deadly. If you hit this spot during the week you’ll probably luck out and find it empty. Stay away during the weekends, it gets crowded.
When I first moved here, I came here with a few friends and it was a cool place to hang out for a little while. You wouldn't make this a day activity, but it's something to do if you're in the Hawai'i Kai area for dinner (Roy's - the famous restaurant by James Beard award winner Roy Yamaguchi - is located here) or something. It's also a good place to stop on your way back from East O'ahu.