Oahu Coral Reef Diving

Hawaiian Diving Adventures

Our daily reef diving starts in the late morning (11:00 am-2:30 pm) and is great for newer divers, or for divers wanting a more casual experience on our shallow reefs. The coral gardens are a quick 10-15 minute boat ride from our harbor. By the time you put on your wetsuit, we are ready to get in the water. We usually see at least one sea turtle on the way out of the harbor!

This trip is for certified divers and first-time, basic divers. We often have groups of all levels on the reef dives, so it is a great way to meet other divers from around the world. Our groups are always small and organized according to experience level. We do not mix certified divers with basic divers unless they are part of the same group and want to dive together.

We usually reserve our afternoon dives (2:30 pm-6:30 pm) for private charters, so call us to book a dive charter in the late afternoon. Night dives (6:30 pm-8:00 pm) are also available upon request.

Hawaii does not have “dive sites” as you find elsewhere. We have amazing, beautiful, and huge reef systems that surround the islands. Here on Oahu, we have several unique reef systems where we regularly dive. These systems are so diverse that we are able to do different dives in the same area. No two dives are ever the same, and our guides deliver a unique experience every time.

Reef System Highlights

Horseshoe Reef/Kewalo Pipe/Rojo

This reef system is one of the largest and nicest coral reefs on the island of Oahu. The reef begins at about 30 feet and extends to at least 70 feet of depth. We have never even found the extremities of this reef system! Where we dive is in an approximately 25-acre area, but we know it extends further. This reef system is home to turtles, eels, octopuses, and a large population of nudibranchs. If you do one reef dive on Oahu, make sure it is on this reef system.

Horseshoe Reef (30'-60' / 9m-18m)


Horseshoe Reef is one of our favorite spots on this reef system, simply for the number of diving options. Depending on what you want to see and do on your dive, Horseshoe Reef has it all. There are a wide variety of corals and plentiful marine life, including eels, octopuses, nudibranchs, and all kinds of colorful reef fish. The reef is shaped like an ‘H’ or a double horseshoe. Simply cruising the perimeter of the coral, or over the top of each coral head, we run into all kinds of interesting things here.

Kewalo Pipe (25'-60' / 7.5m-18m)

We’re not sure where this pipe came from, but it is one of the longest, straightest artificial reefs in Hawaii. The end of the pipe is home to some large moray eels and the start of one of our nicest coral gardens. The trick here is to just go slow. This is home to juvenile reef fish who are skittish and will hide if you swim too quickly. We also see more of the shyer animals in this area, like leaf scorpionfish and Hawaiian lionfish. Macro photographers love this site to see nudibranchs, flatworms, and more small critters.

Secrets Reef (25'-40' / 7.5m-12m)

Although not much of a secret anymore, this fun reef doesn’t have any moorings: the short swim is worth the effort. There are several reef overhangs where turtles and whitetip reef sharks can be found snoozing the morning away, often right next to each other. This is also a great spot to see the resident frogfish, lots of healthy coral, and a high probability of hunting blue trevally. Nudibranchs are very common on Secrets Reef too!

Rojo Deep Reef (45'-60' / 14m-18m)

This is a Hawaiian Diving Adventures exclusive, right in the middle of the most beautiful and expansive coral gardens on the island. Since Rojo Reef is so infrequently visited, there is an excellent chance to spot an elusive dragon moray or snowflake moray (two of the less commonly seen eels in Oahu). Rojo Reef is deep enough that ocean swells do not terribly impact visibility or damage the coral. This site is for more advanced divers, so the coral isn’t damaged by as much traffic. It is definitely an incredible spot to see a wide selection of Hawaiian corals! Although Hawaii is not necessarily well known for soft corals, more than half the species found around Oahu are endemic, and only found in Hawaii.

Nautilus/Neptune's Throne/Turtle Town/Rainbow Reef

This reef system is just offshore from Ala Moana Park. It is a series of finger reefs that stretch approximately one mile from Kewalo Basin to the Ala Wai Harbor. The transition of the reef to rubble, to the reef to rubble means that we get all kinds of animals in these areas. Firstly, large schools of reef fish hang out above the reef. Next, ambush predators like frogfish are seen in the transition zones. Then we find invertebrates like mantis shrimp, harlequin shrimp, and octopuses in the rubbly and sandy areas.

Nautilus Reef (30'-45' / 9m-14m)

One of the “real fishy” reefs in Oahu, we’ve seen a wide variety of relatively rare reef critters here, from the cute Hawaiian turkeyfish to frogfish, and many more. There are some really nice schools of Hawaiian sergeants, oversized parrotfish, and all kinds of colorful wrasses. You have a high chance of spotting nudibranchs, tiger flatworms, and other small creatures too. You can usually spot one or more whitetip reef sharks on this dive, usually snoozing under a reef ledge after their night of hunting. Nautilus Reef is a great place to see species of fish found only in Hawaiian waters, and not found anywhere else in the world. Nearly 30% of the fish you see here simply do not exist outside of the Hawaiian archipelago!

Turtle Town (25'-45' / 7.5m-14m)

This is a really cool shallow reef that doesn’t get much traffic, and there are often six or more turtles waiting for our visit, usually right at the mooring line! On a good visibility day, this is one of the best spots off Oahu. There are all kinds of large stony corals and interesting coral heads holding hundreds of reef fish. Turtle Town is also a great location for exploring some of the sandy areas just off the coral. Lots of different fish and crustaceans call these sand flats their home.

Neptune's Throne (45'-55' / 14m-17m)

Discovered by Hawaiian Diving Adventures in 2014, Neptune’s Throne is an isolated finger of coral surrounded by sand and rubble. Off the beaten path and rarely visited by divers, this is a great mid-depth reef for rare animals and less commonly seen fish. After diving here, it’s easy to guess how we named it: there are a large number of ceramic toilets scattered around the rubble of the coral fingers, which have become home to a wide variety of fish. We’ve seen eels, crabs, and all kinds of critters that call the toilets home! The reef sits in about 50’/15m of water and is a good alternative for people who have already been to some of our larger and more popular reefs.


Turtle Canyons (25'-40' / 7.5m-12m)

This is probably the busiest reef system off the south shore of Waikiki. The shallow reefs have several turtle cleaning stations Here, divers and snorkelers can watch green sea turtles get their shells cleaned by hungry wrasse and tang fish. Turtles hover in the water over the coral heads at the cleaning station, so you get a close look at these gentle giants. Chances of seeing multiple turtles are great, and it’s not uncommon to see a dozen or more. One of our instructors once counted 26 different turtles on a single 50-minute dive here! This reef also has several rocky coral overhangs where whitetip reef sharks hang out. A shallow depth and strong swells coming from around Diamond Head make this area a little more prone to stronger currents and surge, but on light days, it’s a great dive reef to visit.

100' Foot Hole Deep Reef (80'-90' / 24m-27m)

The name is a bit misleading, as there is no hole! Instead, this reef is a large pile of rocks and small coral heads. It’s a fantastic site to watch for pelagic sharks and spotted eagle rays cruising by, curious about what’s going on in the water. Slipper lobsters, sponge crabs, cowries, and some of the other less common Hawaiian invertebrates seem to like this area too!

Please contact Hawaiian Diving Adventures for more information about our various reef dives. When you are ready to go diving, use our online booking form to sign up!