One of the most beautiful beaches this island has to offer. Situated on the west side of Oahu, until you can't drive any further is the amazing Yokohama Bay. Make a day trip out here. Bring a grill and a snorkel and you're all set for the day. They have public restrooms and showers. (If the shore break is active, exercise caution and always listen to the lifeguards. Hawaii shore break is not like anywhere else and Yokohama Bay has some of the strongest on the island)
Home to one of the largest surfing waves in the world where The Eddie (the surfing worlds most prestigious big wave surfing event) is held in honor of the legendary hawaiian big wave surfer Eddie Aikau. When the waves aren't so big it's also home to the famous "waimea jump rock." It's the perfect place for a day at the beach, and if you get there early enough, you might be able to snorkel with the local dolphins who frequent the bay early in the morning.
Across the street from Waimea Bay, is the beautiful Waimea Valley. There, you can walk all the way to the back of the valley learning about native foliage and ancient Hawaiian customs. At the end of the breathtaking walk you will come to Waimea Falls where you can jump in and cool off... if you want to pay for a life jacket that is.