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Hotels, dive operators, gear, and how to get here are on the Kona Coast location page.
Overview
A collapsed volcanic lava tube off Lanai's leeward south coast, southeast of Manele Bay, forms a cavern the size of a small chapel: roughly 30 m long and two stories tall, entered through a wide archway whose floor drops to about 18 m. Where the roof caved in, holes in the ceiling let shafts of sunlight pour onto a fallen block of basalt that divers call the Altar, and on calm summer middays the beams turn the chamber into a stained glass effect that gave the site its name. Walls crusted with orange cup coral shelter green sea turtles, resting whitetip reef sharks, spiny lobster wedged into cracks and clouds of endemic Hawaiian reef fish. The classic finish is the Shotgun, a narrow chimney at the back of the cavern where divers time the surge and get flushed into open water one at a time.
Briefing note
This is a cavern dive in an overhead environment, entered through an archway and finished through a tight chimney called the Shotgun where divers ride the surge out one at a time, so most operators require Advanced Open Water or a confident certified diver with good buoyancy. Sand stirred off the floor clouds the chamber fast, so the first group in gets the cleanest light, and the sunbeams on the Altar are sharpest on calm summer middays near noon. Winter Kona storms and rougher channel crossings cancel trips at short notice.
What you'll see
7 species curated- year-roundGreen sea turtle
- year-roundWhitetip reef shark
- year-roundHawaiian spinner dolphin
- year-roundHawaiian spiny lobster
- year-roundBluestripe snapper
- year-roundMoorish idol
- seasonalHumpback whalePeak: Dec · Jan · Feb · Mar
Reef data for this area
Jurisdiction-level snapshotsBenthic snapshot — NOAA Pacific NCRMP
Main Hawaiian Islands (Pacific NCRMP)
Current mean coral cover
23.5%in 2019
Earlier survey
25%in 2013
↓ -1.5 pts
NCRMP Pacific stratified random benthic transects across MHI. Main Hawaiian Islands mean cover has been relatively stable since the 2014–2015 bleaching event recovery window.
Reported at the jurisdictionscale, not the dive site — the published surveys don’t resolve a single reef. NOAA Pacific NCRMP MHI status report →
Conditions
| Month | Water | Visibility | Current |
|---|---|---|---|
| Jan | 24–25 °C | 15–30 m | mild |
| Feb | 23–24 °C | 15–30 m | moderate |
| Mar | 23–24 °C | 15–30 m | moderate |
| Apr | 24–25 °C | 20–35 m | mild |
| May | 24–26 °C | 20–40 m | mild |
| Jun | 25–26 °C | 20–40 m | mild |
| Jul | 26–27 °C | 25–45 m | mild |
| Aug | 26–27 °C | 25–45 m | mild |
| Sep | 26–27 °C | 25–45 m | mild |
| Oct | 26–27 °C | 20–40 m | mild |
| Nov | 25–26 °C | 15–35 m | moderate |
| Dec | 24–25 °C | 15–30 m | moderate |
Season calendar
Peak season highlighted · current month outlined
Next step
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