They can be broken down into a few different categories, the first and most inclusive list are the beaches that allow you to bring your canine to all parts of the beach. One unfortunate limitation of this group is that no dogs on these beaches are allowed off-leash as opposed to other beaches which do often allow dogs off-leash but do not allow dogs up and into the water.
Several of the beaches require you to keep your canine behind the high tide line. This line is typically marked by debris like seaweed. At these beaches, your dog is also required to remain on a leash at all times. All these beaches can be found on their website. In addition, the Hawaii Humane Society has cultivated a list of leashless beaches and dog parks that you can find on their website.
It turns out that Oahu is an incredibly dog-friendly island, and this place is quite a paradise to enjoy with your four-legged friend. The island asks that you bring your own poop bags and clean up after your dog, but dog-friendly amenities are available freely throughout many of these locations. The views available at most of these beaches are unparalleled, with plenty of place for frisbee games and everything you enjoy on this island. It has some incredibly friendly policies regarding canines at the island and this makes for an incredible destination to bring your dog.