Fantastic! Sometimes called the Forbiden Island it the rim of a dorment volcanio.  Great vis. Lots of seals, clown fish and old Lave Tubes you can enter and exit like swim throughs. 

Located just north of Niihau Island,HI. Access is by boat (all day trip departs from Port Allen, 2 hrs boat ride from Kauai) of sea plane only.

Lehua Crater is also known as Lehua Rock.

Lehua Crater

A volanic crater off the coast of Niihau. One of the only places in the world where you can reliably dive with Hawaiian Monk Seals. Boats leave from Kauai, and it's usually an all day 3-tank trip. Sometimes called the Forbidden Island it the rim of a dormant volcano. Great vis. Lots of seals, clown fish and old Lave Tubes you can enter and exit like swim throughs.

Located just north of Niihau Island, HI. Access is by boat (all day trip departs from Port Allen, 2 hrs boat ride from Kauai) or sea plane only.

Lehua Crater is also known as Lehua Rock.

Vertical Awareness is a 0-star rated scuba dive and snorkel destination in USA, Hawaii, Niihau which is accessible from shore based on 0 ratings.

Vertical Awareness

Arches is a 0-star rated scuba dive and snorkel destination in USA, Hawaii, Niihau which is accessible from shore based on 0 ratings.

Arches

Monolithic lava formations provide for an array of habitats. Ni’ihau has the most amazing labyrinth network of lava tubes in the state. The mouths of the tubes are 100 feet wide and extend back 150 feet+, only to drop into another passageway.

Huge underwater erosional sea caves and arches change the colors around you. This topography is sure to blow your mind. It is the only dive destination in the world where you have an excellent chance to swim with the most endangered marine mammals in U.S. waters, the Hawaiian monk seal.

Boat's leave from Kauai, and it's usually an all day 3-tank trip to get here.

Ni'ihau

good shark diving

one and a half hour boat ride from kekaha, kauai. deep water diving lots of sharks.

South shore

Nohili Point is at the far Western edge of the island just North of the Pacific Missile Range Facility. This is an extreme, open-ocean dive with unpredictable currents. Do not attempt this dive without a guide.

Directions: From Lihu'e, drive West on Highway 50 until the final fork, bearing right on Kao Road as if you are heading to the Polihale State Park. About .25 mile after the fork, turn left as shown in the picture below.

Nohili Point

Ke'e Lagoon is at the Northern most end of the road where you are more likely to find higher surf than normal. In good conditions, it can be a good snorkel site and an easy dive. Only advanced divers should go beyond the barrier reef.

Directions: Simply drive to the end of Highway 560, mile marker 10.

Ke'e Beach

Note: Since 2015, this has been designated as a nursery/recovery area for the fishes and has been a no-entry area for the past 7 years (Haw. Code R. § 13-60.8-6). https://dlnr.hawaii.gov/dar/regulated-areas/haena-community-based-subsistence-fishing-area/

Snorkeling Tunnels is great if you know where to go and are a confident swimmer. Tunnels, also known as Makua Beach, is a deceptively massive snorkeling area. Standing on this wonderful wide, long beach, looking out at the waves breaking on the reef edge offshore, it just does not look like all that big of an area, or that far away to its outer edge. But the reef here is a big horseshoe that protects what amounts to a small bay inside. It is much bigger than it appears when you start trying to swim around in it.

Snorkeling Tunnels is some of the best you can find on the island. It is one of the best places on Kauai for seeing big coral formations. Because it is a large area and there are currents, the snorkeling out on the larger reef is not for beginners, but for strong swimming, experienced snorkelers.

Tunnels, like any north shore Kauai snorkeling spot, is seasonal. Often in the winter the waves are too big and the current too dangerous to attempt to snorkel here. We recommend in the winter to snorkel on the south side of Kauai.

The parking for snorkeling Tunnels is even more scarce than at Ke’e Beach. You must arrive very early in the morning to guarantee yourself a spot here. If you don’t get here early enough to get one of the few spots nearer the beach, you can park farther down the road at Ha’ena Beach Park and walk down the beach to Tunnels area. It is over a half mile walk along the beach. If you don't want to try to find parking, you can ride the Kauai North Shore Shuttle to Ha'ena Beach Park.

Tunnels Beach

The Hideaway is best for snorkeling, if you are in the area. We would call this a good beginner scuba dive, but the climb up and down the bluff can be difficult with 40 pounds of equipment. Definitely take a drive there to check it out for yourself, if for nothing more than admiring the sights of the Princeville Resort.

Directions: On the North coast on Highway 56, turn into the Princeville Resort area at about mile mark 28. Drive 1.5 miles all the way up to just before the Princeville Resort gate, and you'll find beach access parking to the right, next to the tennis courts.

The Hideaway at Princeville

The Lawai Beach park, just next to the Beach House restaurant, has plenty of parking, restrooms, a telephone and shower.

Directions: From Lihu'i heading West on Highway 50, turn left on Highway 520 (Maluhia Road) at mile mark 6.8. After about 3 miles, you'll hit a T in the road at Koloa. Jog right and then an immediate left onto Po'ipu Road, and head South to Po'ipu. At about mile 4.8, take the RIGHT fork and head West. After about a half a mile, you'll have arrived!

Lehua Crater

Snorkeling and Scuba Diving at Lehua Crater