The year in a chart
Nusa Penida manta ray season, month by month
A year around the bays
Twelve months of mantas, sunfish and sea
Choose a month to see sunset, daylight, the usual warmth and what the sighting records say about it.
Sunset
Jan
- Sunset falls near 18:44
- Light lasts around 12.6 h18
- The month in brief: Monsoon, rough sea7
- Daytime lasts near 31°C, night of about 25°C18
The north-west monsoon limited access to the study sites.1
Feb
- Sunset falls near 18:44
- Light lasts around 12.4 h18
- The month in brief: Wet, Manta Bay a little up7
- Daytime lasts near 31°C, night of about 25°C18
Manta Bay sightings ran marginally higher from February to April.1
Mar
Apr
May
- Sunset falls near 18:06
- Light lasts around 11.7 h18
- The month in brief: Manta Point peak7
- Daytime lasts near 31°C, night of about 25°C18
About twice the usual sightings at Manta Point, with reproductive behavior.1
Jun
Jul
- Sunset falls near 18:13
- Light lasts around 11.7 h18
- The month in brief: Dry, Manta Bay a little up7
- Daytime lasts near 29°C, night of about 24°C18
Manta Bay sightings were marginally higher in July.1
Aug
- Sunset falls near 18:17
- Light lasts around 11.8 h18
- The month in brief: Dry, sunfish upwelling7
- Daytime lasts near 29°C, night of about 24°C18
Colder water rises and peaks in August and September.6
Sep
Oct
- Sunset falls near 18:12
- Light lasts around 12.3 h18
- The month in brief: Dry, sunfish still high7
- Daytime lasts near 31°C, night of about 24°C18
Sunfish numbers are still high in Crystal Bay.6
Nov
- Sunset falls near 18:18
- Light lasts around 12.5 h18
- The month in brief: Wet season starts7
- Daytime lasts near 32°C, night of about 25°C18
The wet season runs from November to March.7
Dec
- Sunset falls near 18:32
- Light lasts around 12.6 h18
- The month in brief: Monsoon, rough sea7
- Daytime lasts near 31°C, night of about 25°C18
The monsoon again limited access to the study sites.1
Sunset is worked out for the 15th of each month on Bali time (UTC+8) at the island's coordinates. Day length is calculated; temperatures are averages from the GHCN-Daily record of Denpasar airport, 41 km from Nusa Penida across the Badung Strait, 1991 to 2020. The island has no station of its own.
Mantas live around Nusa Penida all year, yet a few months stand out in the sighting records and a few get in the way of the boats. Here is what the research, the weather agencies' seasons and the tour listings each say about timing.
Editorial team, nusapenidasnorkeling.quest · Updated November 3, 2026 · Reading time about 6 min
Begin with this
- All twelve months of the yearResearchers logged manta rays at the island's reefs year-round, with 624 individuals identified from 5,913 sightings.1,2
- The high pointManta Point recorded about twice as many sightings in May, and mating behavior peaked then too.3,4
- The rough monthsDecember and January, the north-west monsoon, limited access to the study sites.5
- SunfishSunfish occurrences in Crystal Bay run from August to October.6
- The trip we featureOur snorkel session lists a manta sighting rate of about 30 percent, from $17.
Mantas do not leave when the calendar says so
Anyone searching for a manta ray season at Nusa Penida expects a start date and an end date, the way a whale watch has one. The best evidence says the animals do not work like that. A long photo-identification study, run with the help of citizen scientists, logged year-round records at two shallow reefs, and across 2012 to 2018 it identified 624 reef manta rays from 5,913 sightings.1
The same paper states that manta rays are present in the marine protected area throughout the year.2 The question is not whether mantas are around in a given month. It is how likely you are to meet one on a given morning, which has more to do with the site, the tide, the swell and luck than with a date range.
That is also why tour listings word their promises carefully. Our own listing says manta sightings are not guaranteed and depend on weather, sea conditions and the time of year. Treat any month as a fair month for an attempt, and read the rest of this page as a way to improve your odds, not to find a safe window.
Six stretches of the year
Manta, sunfish and sea by period
| Period | Manta Point | Manta Bay | Sea and weather |
|---|---|---|---|
| Dec through Jan | Fewer survey days | Fewer survey days | North-west monsoon |
| Feb to Apr | Ordinary | Slightly up | Wet season fading |
| May | Peak, about double | Ordinary | Dry season begins |
| Jun to Jul | Ordinary | July slightly up | Rain-light months |
| Aug through Oct | Ordinary | Ordinary | Cold-water upwelling |
| Nov | Ordinary | Ordinary | Wet season starts |
Sightings follow the photo-identification study of 2012 to 2018; the monsoon months follow its survey notes, and the seasons the tourism ministry's two-season description.1,4,5,6,7
May, the month the sighting counts point to
If one month deserves to be marked in a diary, the research marks May. At Manta Point the number of manta sightings roughly doubled in that month compared with the rest of the year.4 The paper adds that reproductive behavior coincided with the peak annual sightings in May.3
Manta Bay, about 12 km away, told a flatter story. Sightings there were only marginally higher from February to April and in July than in the other months.4 A visitor planning around the data would weigh May for Manta Point, and treat the other months as ordinary at both sites.
There is a catch the authors raise themselves. They suggest regulating the number of boats and the interactions during the key reproductive times.3 The paper also says this population is under chronic pressure from tourism.2 The best month for mantas is also a month when a calm, patient guide matters more than a fast boat. Ask any operator how many boats share the reef at once, and whether the guide will move the group away when the rays are busy with each other.
Rain by month, mainland
How wet each month is at Denpasar
Two reefs, two kinds of morning
Manta Bay and Manta Point are both shallow bays between 7 and 25 meters deep, fringed by steep rocky cliffs and deep water, about 12.4 km apart.12 Yet the rays use them differently. Manta Bay appears to be a foraging ground, especially for juveniles, and possibly a nursery, while Manta Point is used mainly for cleaning and courtship.13
The mix of animals follows the use. At Manta Bay the identified rays were mostly male, with immature males the most frequently sighted, while at Manta Point mature females were the most frequently sighted.14 Individuals travel between the two as well: 44 percent of those identified moved from one site to the other.15
For a snorkeler this means a morning at Manta Bay tends to be about rays that are feeding, often young ones, and a morning at Manta Point is about rays hovering over a cleaning station. Both scenes are worth a trip, and our guides to each spot describe them in more detail. Reef manta rays measure typically 3 to 3.5 m across the disc.16 A close pass is hard to forget.
Which month for you
Which stretch of the year fits you?
Match what you care about with a period and its evidence
If I want the busiest manta month
May
Manta Point sightings roughly doubled in May in the study.4
If I want the driest weather
From April until October
These are the dry-season months in most of the country.7
If I hope to see sunfish
August until October
That is when sunfish numbers are high in Crystal Bay.6
If I can only travel in the wet months
Pick a refundable booking
Our listing carries free cancellation until a day ahead.
If I do not mind the date
In any month at all
Mantas were recorded year-round.2
What the listings say about your chances
Listings are marketing, so read their numbers as the operator's own estimate and not as a measurement. Our snorkel session states that sightings at Manta Bay happen roughly 30 percent of the time, depending on weather, sea conditions and the season. A private-boat listing that starts on the island gives the same 30 percent for Manta Bay.
A private Manta Point listing from Bali is more upbeat. It says there is approximately a 90 percent chance of meeting manta rays at Manta Point, again depending on weather, sea state and season, and it adds that sightings cannot be guaranteed. The gap between 30 and 90 percent is large. It matches the research in one respect: the study places the cleaning and courtship behavior at Manta Point.13
A diving listing for certified divers says manta sightings are common year-round and names July to October as the best months for mola-mola. None of these numbers comes from a survey you can check. Use them to compare sites and not to plan a promise.
A year at the bays
What each stretch of the calendar offers
Dec through Jan
Monsoon stretch
The north-west monsoon limited access to the study sites in these months.5
Feb to Apr
Quiet lift at Manta Bay
Manta Bay sightings ran marginally higher in these months.4
May
The Manta Point peak
About twice the usual sightings at Manta Point, with reproductive behavior.4,3
Jun to Jul
Dry months, little rain
Part of the dry season from April to October, with Manta Bay slightly up in July.7,4
Aug through Oct
Sunfish upwelling
Colder water peaks in August and September; sunfish are high in Crystal Bay.6
Nov
Wet season returns
The wet season runs from November to March in most of the country.7
Dry spells, wet spells and the sea in between
Indonesia's tourism ministry describes two seasons rather than four. Across most of Indonesia, Bali and Java among them, the dry months are April to October and the wet months November to March.7 The ministry also notes that the seasons have become less predictable.17 Nusa Penida's climate is drier than Bali's, so treat the mainland pattern as a rough guide here.11
Rain is only part of the picture for a boat day. The study team found that in the north-west monsoon season, December and January, unfavorable weather limited access to its study sites and cut the survey effort.5 If a snorkel trip is about getting to a bay on the day, the rough-sea months are the ones to treat with the most flexibility, and a booking with free cancellation helps.
For scale, the Japan Meteorological Agency's long-term averages for Denpasar, on the mainland, put January as the wettest month shown here at 350.7 mm and July as the driest at 27.6 mm.8,9 That is a mainland airport, not the island, but the swing from a very wet month to a very dry one shows why the dry months from April to October are the usual choice for a boat day. Air temperature barely moves across the year: that airport averages a daily high of 29.2 °C in July against 31.7 °C in November.18,18
Video
Seeing manta rays at Nusa Penida for the first time
Jess and Dave on YouTube · The video stays still until you press play.
Reproductive behavior coincided with the peak annual sightings in May.
Checklist
Fitting the trip to the season
Name the date3
- Pick a booking you can cancel free until 24 hours before
- Lean toward April to October for drier weather
- Leave a spare day in case the sea is too rough
Choose the site3
- Manta Point for cleaning-station behavior
- Manta Bay for feeding rays, often juveniles
- Ask the guide which of the two is calmer that morning
Treat the rays well3
- Never touch, feed or chase a manta
- Choose a guide who keeps the boat count low
- Wear a life jacket as the listings advise
Sunfish months are a separate calendar
Some visitors say manta season and mean the big ocean animals in general. Sunfish keep their own timetable. A study of sea-surface temperature near Nusa Penida found that upwelling of colder, plankton-rich water peaks in August and September, and that it coincides with high numbers of ocean sunfish in Crystal Bay from August to October.6
A paper on giant sunfish tagged around Bali adds that the species is seasonally important for scuba tourism, and the fish seek out cleaner-fish on the reefs of the marine protected area.19 That is a diver's season. A snorkel session over shallow reef is not designed to reach the depths where sunfish are usually met, so treat sunfish as a bonus of a dive trip and not a reason to book a boat. If sunfish are the goal, the page on snorkeling or diving explains what a dive day involves and who it suits.
The takeaway for dates is simple. May suits the manta data at Manta Point, August to October suits sunfish, April to October is the dry season, and December to January is the stretch where weather most often stands between you and the bay. Whichever month you choose, book the earliest start the listing offers, keep the afternoon free for a second attempt if the operator allows it, and remember that a day without a manta can still hold turtles, reef fish and a clear bay.
FAQ
Short questions, plain replies.
When is the best month to see manta rays at Nusa Penida?
Can I see manta rays in every month?
Manta rays were present in the marine protected area throughout the year, though a sighting on any one trip is never promised.2
How likely is a manta sighting on a snorkel tour?
A private Manta Point listing states approximately 90 percent for that site, and none of the figures are guaranteed.
Is Manta Bay or Manta Point better for seasons?
Manta Bay sightings were only marginally higher from February to April and in July.4
Which months are rough for boats?
The north-west monsoon limited access to the study sites in those months.5
When is sunfish season at Nusa Penida?
Upwelling of colder water peaks in August and September and matches high sunfish numbers.6
Are manta rays protected in Indonesia?
Ministerial Decree 4/2014 protects both manta species in the whole exclusive economic zone.20
What size are the manta rays here?
That is the typical disc width of the reef manta ray, with a maximum of about 5.5 m.16
Sources
- Frontiers in Marine Science (peer-reviewed; authors include the Ministry of Marine Affairs and Fisheries, Indonesia) · Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia ↩
- Frontiers in Marine Science (peer-reviewed; authors include the Ministry of Marine Affairs and Fisheries, Indonesia) · Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia ↩
- Frontiers in Marine Science (peer-reviewed; authors include the Ministry of Marine Affairs and Fisheries, Indonesia) · Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia ↩
- Frontiers in Marine Science (peer-reviewed; authors include the Ministry of Marine Affairs and Fisheries, Indonesia) · Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia ↩
- Frontiers in Marine Science (peer-reviewed; authors include the Ministry of Marine Affairs and Fisheries, Indonesia) · Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia ↩
- IOP Conference Series: Earth and Environmental Science · Sea surface temperature variability and ocean sunfish occurrences in Nusa Penida, Bali (Tito and Susilo) ↩
- Indonesia Travel (Ministry of Tourism, Republic of Indonesia) · Indonesia Travel guide to weather, climate and the seasons ↩
- Japan Meteorological Agency · JMA climate normals for Denpasar, Indonesia: monthly mean temperature and rainfall ↩
- Japan Meteorological Agency · JMA climate normals for Denpasar, Indonesia: monthly mean temperature and rainfall ↩
- Japan Meteorological Agency · JMA climate normals for Denpasar, Indonesia: monthly mean temperature and rainfall ↩
- Wikipedia · Nusa Penida ↩
- Frontiers in Marine Science (peer-reviewed; authors include the Ministry of Marine Affairs and Fisheries, Indonesia) · Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia ↩
- Frontiers in Marine Science (peer-reviewed; authors include the Ministry of Marine Affairs and Fisheries, Indonesia) · Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia ↩
- Frontiers in Marine Science (peer-reviewed; authors include the Ministry of Marine Affairs and Fisheries, Indonesia) · Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia ↩
- Frontiers in Marine Science (peer-reviewed; authors include the Ministry of Marine Affairs and Fisheries, Indonesia) · Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia ↩
- Wikipedia · Reef manta ray ↩
- Indonesia Travel (Ministry of Tourism, Republic of Indonesia) · Indonesia Travel guide to weather, climate and the seasons ↩
- NOAA GHCN-Daily archive kept by NCEI GHCN-Daily archive kept by NCEI · Denpasar Ngurah Rai airport station record of daily highs and lows (GHCN-Daily), Station Ngurah Rai airport at Denpasar (GHCN-Daily IDM00097230), 1991 to 2020 ↩
- Marine Ecology Progress Series (Inter-Research) · Overcoming challenging telemetry data of giant sunfish Mola alexandrini in Bali, Indonesia ↩
- Frontiers in Marine Science (peer-reviewed; authors include the Ministry of Marine Affairs and Fisheries, Indonesia) · Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia ↩
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