We are creating a Top Question to cover frequently asked questions about what Big Island beaches are "the best". Obviously there is no "best" since every beach is unique in its way, and some beaches are good for snorkeling, others swimming, and others body boarding, etc., so it depends in part on what people are looking for. I'm going to kick this off with my favorites. Please feel free to add to this list. We will have another topic for east side beaches. Please limit your responses to *beaches* as this topic is intended to answer people's questions who want to spend time on a sandy beach. Thus, places like Kahaluu and Honaunau, covered under the snorkeling TQ, would not be appropriate topics for this particular question as they are not beaches per se.
I am going to kick things off with my favorites, listed in order as you head north starting with Kikaua Point. Visitors are requested (but by no means obliged) to try to avoid beaches on weekends if possible, as those are precious free times for local residents and families. Visitors will also find far less people and parking difficulties at area beaches on weekdays, so it's to their benefit as well, although few Big Island beaches are ever crowded.
This is by no means a comprehensive list so other replies are needed to make certain this is a good resource for the TQs. It is helpful to include not only what you like about the beach, but also access and if there are facilities.
KEKAHA KAI STATE PARK (Mahai'ula, Makalawena, and Manini'owali):
MAHAI'ULA and MAKALAWENA
No rental cars are allowed down the bumpy, unpaved, Kekaha Kai State Park road, which leads to Mahai'ula. Non-rental 2wds can make the drive, however. Otherwise, you can either park at Manini'owali (listed below) and walk the shoreline south to Makalawena and then Mahaiula, or you can park off the highway and hike in, but make sure you leave NOTHING in your rental car. There are only portable "luas" for restrooms. This is a beautiful shoreline area. The snorkeling is nothing to speak of, nor is the bodyboarding or swimming, really the attraction here lies in the fine, light colored sand, the contrast with the shifting shades of blue, and the lack of people on weekdays (this is a very popular area on weekends with local residents). From Mahai'ula, you can walk either the lava path behind the beach to Makalawena, or walk the shoreline to Makalawena. You can also park further up off the highway and hike straight down to Makalawena.
MANINI'OWALI (Kua Bay).
Very popular with residents. Paved road in. Primary use is bodyboarding and bodysurfing. Dangerous shore break when surf is up. Very nice, fine, light colored sand but there can be little of it in times of high surf. Lovely turquoise water. Snorkeling is not a primary activity but if it's flat there are fish and some coral heads out at the points. Walking to the beach from the parking lot requires stepping down and over some rocky areas so this isn't a good beach for anyone with access issues.
KIKAUA POINT/KUKIO BAY
Located between Kua Bay (Manini'owali) and the Four Seasons Hualalai, approximately 25 minutes north of Kailua-Kona and 25 minutes south of the Kohala Coast resorts, Kikaua Point and Kukio Bay consist of a stunning series of coves, beaches, lagoons, wetlands, and fishponds. Entry from the highway is either through the gated residential development of Kukio (Kikaua Point side) or the gated Four Seasons Hualalai (Kukio Bay side). Both guard gates issue day passes to the beaches that are generally available except occasional weekends when weddings or holidays cause the public access lots to fill up. Aside from the fish ponds, wetlands, and peaceful lagoon, attractions here include the many turtles, engangered birds, and occasional monk seal that visit the area. Black crested herons and Hawaiian stilts (ae'o) are in abundance.
There is good snorkeling at high tide in the small area beyond the lava rock sea arch in the lagoon at Kikaua Point, known as The Aquarium. Eels, octopus, and occasional reef sharks can be seen in the bay, fringed by lava rock, located immediately to the south of the public access lot on the Kikaua Point side. There are many turtles to be seen in the water on the south end of Kukio Bay as well as resting on the sand, and this is a popular spot with a resident monk seal. Do not approach seals or turtles resting or swimming in the Bay.
There are restrooms and showers both at the Kikaua Point and Kukio Bay sides of this beach area. You can walk approximately 15 minutes along the ocean on a paved golf cart path from Kukio Bay to the Four Seasons for lunch at either the Resident's Beach House or the Beach Tree, both of which have some of the best food (and cocktails) on the island.
Beautiful, small, black(ish) sand beach with lava rock cliffs and a shoreline fisherman's trail, located in a luxury residential development within the Mauna Lani resort complex known as 49 Black Sand Beach. Very clear water, excellent, unspoiled reef. Pinnacles and reef in shallower water to the left (south), deeper reef to the right (north). Entry is easy, but there is a little drop off and small rocks all along the shoreline. Reef shoes recommended for entry and exit. Manta ray cleaning station approximately a half mile across the bay, large ulua, barracuda, and schools of fish often seen.
Note: The sand is VERY hot here, particularly in summer.
Lovely, small, golden sand beach on the south end of the Mauna Lani resort property. Surrounded by the ancient fishponds of Kalahuipua'a. There is a beach club with a restaurant called Napua that is nice for lunch or dinner and has live local music on Thursday-Sunday evenings.
Easy entry and exit, shallow reef with immediate payoff of reef fish, coral heads, octopus, and eels. The water clears as you continue out, and the dramatic coral pinnacles increase, as well as larger schools of fish, and larger fish. Experienced swimmers in flat ocean conditions can head left (south) along the shoreline outside of the bay to see larger fish, larger schools, and, in about a half mile, just before the entry to Honokaope (above), large coral fingers in about 30 feet of water.
There are restrooms as well as showers, but the showers are on the beach so no shampoo or soap use is allowed.
This gorgeous beach, sometimes called "Beach 69," (please use the proper name "Waialea Bay") is located in South Kohala on the Kohala Coast, just north of Puako and a couple of minutes south of Hapuna. Here there is excellent snorkeling in summer as well as other times when there are not or have not been recent north and northwest swells. There can be rip currents and sudden larger swells, so exercise caution, but experienced swimmers and snorkelers will love the "points" on either end of the bay as well as the large reef in the middle of the bay. Very close to shore less experienced snorkelers can still see beautiful, healthy coral reef and many fish as well as turtles and eels.
Parking can be difficult on weekends and later in the day, but even when full, the beach itself does not seem crowded, it is quite large. The sand is peppered with thorns from the overhanging trees (which provide many nice shady spots) so make sure to wear slippahs with good soles and watch small children with tender feet. There are some beach houses for rent along this Bay, which is unique on the island. There are restrooms and showers. There is a $5 entrance fee for non-residents.
This beach situated in front of the Mauna Kea Beach hotel is one of the most beautiful beaches in Hawaii thanks to the very light, almost white, fine sand. It is also one of the bigger beaches on the Big Island, and has excellent swimming when flat. Unfortunately, the hotel has thumbed its nose at the intent of public access laws, and only a few parking places are designated for public access. Due to the popularity of this beach, it can be difficult to get a pass unless you get there prior to 9am. Public restrooms and showers are available, and the Mauna Kea hotel has a beach bar/restaurant that is open to the public on the north end. There is also a shoreline path (not maintained, but still walkable) between Hapuna, below, and Kauna'oa. One option if no passes are available is to park at Hapuna and walk to Kauna'oa.
Easily the most popular beach on the Big Island, due to its length and quality of sand. Fronting the Hapuna Prince hotel, this beach in winter can have a very dangerous shore break and injuries and even fatalities are unfortunately far too common. This is the most crowded beach on the island, but still is not packed with people by any means, particularly on the north (hotel) side. With smaller waves, it is a great beach for bodyboarders and bodysurfers. There is excellent swimming when conditions permit. Restrooms and showers. There is a $5 entrance fee for non-residents.