Kona Manta Ray Night Snorkel: Moon Calendar
Where the moon sits over the 7 to 10 PM dive window, for the next 90 nights.
Does the moon matter?
Not the way it usually gets told. The rule of thumb is to book a new moon: a dark sky makes the boat lights a stronger beacon for plankton, more plankton means more mantas. It is a tidy story, and the boats themselves do not agree on it. Some swear by the new moon. One of Kona's busiest operators puts the full moon at the top of its list. Another says flatly that they see big groups in every phase of the month.
So we checked it. Jack's Diving Locker publishes what they saw on every night they ran, and we lined 308 of those nights up against where the moon actually was during the dive window. Nights under 10% illumination averaged 10.8 mantas. Nights over 90% averaged 12.1. With the moon down for the whole window the average was 10.6, with it up the whole time, 10.3. There is no signal in that.
Mantas show up on something like 85 to 90% of nights, all year round. What moves the numbers is plankton, and plankton follows currents and water temperature rather than the sky. So book the night that fits your trip.
The season does matter, though. April to October is the calm stretch on the Kona coast; winter brings the swells that cancel trips outright. That is the thing worth planning around.
The moon, night by night
Computed for sea level off Kona, between Manta Village and Manta Heaven. Times are Hawaii time.
October 2026
| Night | Moon | Over the window |
|---|---|---|
| MonOct 19 | 65% | Up all evening |
| TueOct 20 | 74% | Up all evening |
| WedOct 21 | 83% | Up all evening |
| ThuOct 22 | 90% | Up all evening |
| FriOct 23 | 95% | Up all evening |
| SatOct 24 | 99% | Up all evening |
| SunOct 25 | 100% | Up all evening |
| MonOct 26 | 98% | Up all evening |
| TueOct 27 | 94% | Rises 7:16 PM |
| WedOct 28 | 87% | Rises 8:16 PM |
| ThuOct 29 | 78% | Rises 9:21 PM |
| FriOct 30 | 68% | Down all evening |
| SatOct 31 | 57% | Down all evening |
November 2026
| Night | Moon | Over the window |
|---|---|---|
| SunNov 1 | 45% | Down all evening |
| MonNov 2 | 35% | Down all evening |
| TueNov 3 | 25% | Down all evening |
| WedNov 4 | 16% | Down all evening |
| ThuNov 5 | 9% | Down all evening |
| FriNov 6 | 4% | Down all evening |
| SatNov 7 | 1% | Down all evening |
| SunNov 8 | 0% | Down all evening |
| MonNov 9 | 1% | Down all evening |
| TueNov 10 | 4% | Down all evening |
| WedNov 11 | 8% | Sets 7:41 PM |
| ThuNov 12 | 14% | Sets 8:34 PM |
| FriNov 13 | 21% | Sets 9:27 PM |
| SatNov 14 | 30% | Up all evening |
| SunNov 15 | 38% | Up all evening |
| MonNov 16 | 48% | Up all evening |
| TueNov 17 | 58% | Up all evening |
| WedNov 18 | 68% | Up all evening |
| ThuNov 19 | 77% | Up all evening |
| FriNov 20 | 85% | Up all evening |
| SatNov 21 | 92% | Up all evening |
| SunNov 22 | 97% | Up all evening |
| MonNov 23 | 100% | Up all evening |
| TueNov 24 | 99% | Up all evening |
| WedNov 25 | 96% | Rises 7:04 PM |
| ThuNov 26 | 90% | Rises 8:13 PM |
| FriNov 27 | 81% | Rises 9:21 PM |
| SatNov 28 | 72% | Down all evening |
| SunNov 29 | 61% | Down all evening |
| MonNov 30 | 50% | Down all evening |
December 2026
| Night | Moon | Over the window |
|---|---|---|
| TueDec 1 | 39% | Down all evening |
| WedDec 2 | 29% | Down all evening |
| ThuDec 3 | 21% | Down all evening |
| FriDec 4 | 13% | Down all evening |
| SatDec 5 | 7% | Down all evening |
| SunDec 6 | 3% | Down all evening |
| MonDec 7 | 1% | Down all evening |
| TueDec 8 | 0% | Down all evening |
| WedDec 9 | 1% | Down all evening |
| ThuDec 10 | 5% | Sets 7:21 PM |
| FriDec 11 | 9% | Sets 8:14 PM |
| SatDec 12 | 15% | Sets 9:06 PM |
| SunDec 13 | 23% | Sets 9:58 PM |
| MonDec 14 | 31% | Up all evening |
| TueDec 15 | 40% | Up all evening |
| WedDec 16 | 50% | Up all evening |
| ThuDec 17 | 61% | Up all evening |
| FriDec 18 | 71% | Up all evening |
| SatDec 19 | 80% | Up all evening |
| SunDec 20 | 89% | Up all evening |
| MonDec 21 | 95% | Up all evening |
| TueDec 22 | 99% | Up all evening |
| WedDec 23 | 100% | Up all evening |
| ThuDec 24 | 98% | Up all evening |
| FriDec 25 | 93% | Rises 8:08 PM |
| SatDec 26 | 85% | Rises 9:14 PM |
| SunDec 27 | 76% | Down all evening |
| MonDec 28 | 66% | Down all evening |
| TueDec 29 | 56% | Down all evening |
| WedDec 30 | 45% | Down all evening |
| ThuDec 31 | 35% | Down all evening |
January 2027
| Night | Moon | Over the window |
|---|---|---|
| FriJan 1 | 26% | Down all evening |
| SatJan 2 | 18% | Down all evening |
| SunJan 3 | 11% | Down all evening |
| MonJan 4 | 6% | Down all evening |
| TueJan 5 | 2% | Down all evening |
| WedJan 6 | 0% | Down all evening |
| ThuJan 7 | 0% | Down all evening |
| FriJan 8 | 2% | Sets 7:02 PM |
| SatJan 9 | 5% | Sets 7:54 PM |
| SunJan 10 | 10% | Sets 8:44 PM |
| MonJan 11 | 17% | Sets 9:34 PM |
| TueJan 12 | 25% | Up all evening |
| WedJan 13 | 34% | Up all evening |
| ThuJan 14 | 44% | Up all evening |
| FriJan 15 | 55% | Up all evening |
| SatJan 16 | 65% | Up all evening |
The window is 7 to 10 PM HST, which is when most groups are actually in the water. Boats leave around sunset and the ride out takes a while.
What a dark night does change
The background. On a dark night the lights hang in black water, the plankton swirl in the beam, and a manta coming up underneath has nothing behind it. Under a full moon you can make out the surface, the hull, the other snorkelers, and the whole scene reads flatter.
Photographers care about this a lot. Most people care about it a little. If you have a free choice of dates and you want the dramatic version, take a night with the moon already down.
What you should not do is skip a night because the moon is bright. On the numbers, you would be giving up an evening for nothing.
What we checked
Jack's Diving Locker's public sightings log, every night they ran and counted between April 13, 2025 and June 29, 2026. That is 308 nights, counts running from 0 to 37, averaging 10.6 mantas a night.
For each of those nights we computed the moon's illumination at 8:30 PM and how long it was above the horizon between 7 and 10 PM, at sea level off Kona. The rank correlation between manta count and illumination came out at 0.09, which is nothing, and it is not statistically significant. Split by season it changes sign: in the calm months the darker nights ran about one manta ahead, in winter about one and a half behind. That is what noise looks like.
What it cannot tell you: nights they did not run are missing from the log, and cancellations track swell rather than the moon. It is one operator's count, not an island-wide census. It is still 308 more nights than the rule of thumb was ever built on.
Tours & booking
Book the boat
Any night on the calendar above works. The same page lists the boats running both sites.
How the manta night snorkel actually works, and which site to pick
Typically $110 to $180 a person out of Kona.
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Check today's Kona surf and ocean conditions
Every full and new moon for the next year, on the Hawaiʻi moon calendar
Moon positions are computed with astronomy-engine for 19.75°N, 156.05°W at sea level, and match the US Naval Observatory to the minute. Sighting figures are from Jack's Diving Locker's published nightly log; the analysis is ours. Operator sighting rates are the ranges Kona boats publish themselves.