Waialae/Kahala Beach is just past Diamond Head a couple of miles east of Waikiki.
The beach area we use is up the beach, about a 200 yard walk from the parking, and fronting a luxury low-rise condo building. If you have mobility challenged people, look at Waimanalo or Magic Island.
We perform ceremonies either on the sand or on one of the grass spots under the shade of the coconut trees. There are about 4 spots we can use. We use which ever area is available. Unfortunately, the best spot shown in many of our sample photos has been torn up and is no longer available.
We recommend ceremony times at 9 am or 10 am. It's much cooler, good for photos, less busy, and parking is generally available. While we don't suggest it but, we can go later.
The parking lot holds about 40 cars and parking can be impossible. 10 am and earlier are normally OK with stalls available. By 11, it can be filled-up for the rest of the day. We suggest using our limousine or just get a taxi or Uber.
We used to use this beach all the time but, in the last couple of years, not so much for the simple reason that the attributes which made it a good spot are diminished significantly.
Except for the early morning (but no guaranty), it's just really busy and congested nowadays. It must be listed in the tourist pamphlets because, the beach and ocean are always busy, Japanese and Chinese wedding companies "camp out" to do photos all day, and other wedding companies do the same, especially in the afternoons. Plus, there's no parking. We suggest looking at our Waimanalo spot if you want to be on the beach or Magic Island if you have a large group and/or just want something easy.
FYI: Any wedding company that suggests or agrees to a ceremony after 11 am with more than a single carload or more than 8 participants, is doing you a great disservice unless, they also suggest a single large vehicle transport for everyone. This is not a location for large groups!
FYI: For ceremonies at 11 am or later, we suggest adding an extra 30 minutes just in case you have to wait for a parking stall if driving on your own (which you should not do).