Swimming With Manta Rays in Bali: An Ethical Guide

Reef manta ray gliding over a sandy lagoon. Photo: naushad mohamed, Unsplash

A wide, dark shadow turns slowly below you. And you have the strange feeling that it is the one deciding how this meeting goes. That is the heart of ethical manta swimming in Bali. Around Nusa Penida, reef manta rays (Mobula alfredi) visit a few shallow sites where people can snorkel or dive with them, and the encounter is only good when it stays on the manta's terms. No touching, no chasing, a calm operator, and acceptance that the sea, not the schedule, decides.

Mantas are not "sights" to collect. They are animals with complex behaviour, and they deserve quiet observation, not pursuit. This guide looks at what science says about them, what makes Nusa Penida special and demanding, and what an ethical encounter looks like in practice.

Beyond the surface: what we know about manta minds

Manta rays are sometimes called the "birds of the sea" for the slow, wing-like beat of their fins. They also have unusually large brains. In a 2016 study in the Journal of Ethology, Csilla Ari and Dominic D'Agostino described mantas as having the largest brain of any fish, with a high brain-to-body ratio similar to some animals that have passed mirror self-recognition tests.

The same study is the source of the famous "manta in the mirror" story. The researchers placed a mirror in the tank of two captive giant manta rays and reported unusual, repeated movements in front of it. They read these as possible "contingency checking" and self-directed behaviour. An intriguing result, but not a settled one. Researchers linked to the Manta Trust published a response arguing that similar movements are common in normal social interactions between wild mantas, so the behaviour may be social, not self-aware. And the full self-recognition test was not completed. The honest summary: mantas are clearly capable animals, and whether they recognise themselves is still an open question. Either way, they deserve a calm approach.

Manta Bay and Manta Point: the Bali context

The best data on Nusa Penida's mantas come from a photo-identification study published in Frontiers in Marine Science in 2019 by Germanov and colleagues. Each manta has its own pattern of spots on its belly. Using photos from researchers, trained observers and citizen scientists, the team identified 624 individual reef manta rays from 5,913 sightings between January 2012 and April 2018. Almost all the records came from two shallow reefs, both under 20 metres deep and both busy with tourism: Manta Bay and Manta Point. As the paper's title says, the mantas use these two sites in contrasting ways, which is why the experience can feel different at each. Our article on Manta Point vs Manta Bay explains that difference.

The same paper is honest about the pressure. It cites an estimate of about 200,000 tourists a year visiting the Nusa Penida Marine Protected Area in 2015, growing by about 7.7 percent a year, and says manta watching is a major reason people come. At the time of the study, the number of boats allowed into manta habitat was not regulated. The authors suggested limits on boats and interactions, especially at important times for reproduction. We do not know of newer published counts, so we cannot tell you whether the population has grown or shrunk since 2018.

Respecting the power of the ocean

At Nusa Penida, the animals are not the main risk. The water is. The island's south coast faces the open Indian Ocean, so swell, surge near the cliffs and currents can change quickly. Fins are essential even for strong swimmers, and an experienced local guide who reads the conditions on the day is not optional. If you are not a confident ocean swimmer, staying on the boat and watching the mantas glide below is a safe and still remarkable choice. A well-fitting low-volume mask and snorkel also helps more than people expect, because a leaking mask in swell turns calm into panic very fast.

How do you swim with manta rays ethically in Bali?

This is the conservation layer, and it is simple. The best manta encounter is the one where the animal chooses to come to you. The rules we follow: never touch a manta, never chase it or block its path, enter the water quietly without splashing, no flash photography, and let the manta set the distance. Published codes of conduct for manta tourism differ in their details, including distances, so always follow your local guide's briefing. If a manta swims closer on its own, that is the moment to stay still and simply watch.

Respect also means fewer people in fewer places. Given the boat numbers described in the 2019 study, one of the most useful things a visitor can do is choose an operator who limits group size, waits instead of joining a crowd of boats, and leaves when a site is busy. For more detail, read our guide on responsible manta diving at Nusa Penida. A long-sleeved rash guard is also kinder to the water than lots of sunscreen at a busy shallow site.

Wildlife encounters are unpredictable. Swimming with manta rays should always follow local regulations and experienced professional guidance.

Bali's tourism rules: what to know before you go

Bali has been moving toward "quality over quantity" tourism, and a few practical things have changed. Since 14 February 2024, foreign tourists pay a levy of IDR 150,000 (about USD 10) each time they enter Bali, under Bali Provincial Regulation No. 6 of 2023 (Article 5). The regulation says the money goes to protecting Balinese culture and the natural environment, though some reporting notes that how it is spent has not been fully explained.

In April 2025, Governor Wayan Koster issued a circular on waste that, according to press reports, bans producing and distributing single-use plastic bottled drinking water under one litre in Bali. We could not find the official text of the circular, reports differ on the timing of each phase, and a court challenge by a producer was reported to have failed. Please check the current rule with the Bali provincial government before you travel. A travel kit with a refillable water bottle fits this new reality well.

Nusa Penida has also charged visitors a separate fee for the marine protected area in recent years. We could not confirm the current amount or how it is collected, so please ask your operator and check the current rule before you travel.

Progress over perfection

Ethical travel is not about being a perfect tourist. It is about being an intentional one. Let us also be honest: flying to Bali has a real carbon cost, and the mantas' biggest problems (fishing gear, boat traffic and a changing ocean) are bigger than any one trip. What we can choose is how we behave when we are there. Small groups, no touching, no chasing, operators who employ and train local guides, and respect for the rules Bali and Nusa Penida are building.

If you want to understand what the mantas are actually doing when they hover over a reef, our piece on manta ray cleaning station behaviour is a good next read.

What we hold ourselves to

Small groups, never more than six guests on our hosted retreats, to keep things safe and our footprint light.
Wildlife encounters that happen on the animal's terms, never ours, and that anyone can skip.
Working alongside vetted local professionals.
Sharing information as honestly and currently as we can, including what we do not know.

If this made you curious about Bali's ocean, you can read about Bali freediving on the quiet north-east coast in Amed. This is not a hosted retreat: through Ocean Match we connect you with a vetted local team that you book directly. Please note it is not built around the Nusa Penida mantas.

Questions people ask

How many manta rays live around Nusa Penida?

A 2019 photo-identification study identified 624 individual reef manta rays from 5,913 sightings between 2012 and 2018. We do not know of a published update with more recent numbers.

Are manta rays self-aware?

Not proven. A 2016 mirror study with two captive giant mantas suggested it might be possible, but other researchers argued the behaviour could be normal social behaviour, and the full test was not completed.

Do I have to pay a tourist levy in Bali?

Yes. Since 14 February 2024, Bali Provincial Regulation No. 6 of 2023 asks foreign tourists to pay IDR 150,000 each time they enter Bali. Rules and exemptions can change, so check the current rule with the Bali provincial government before you travel.

Can I buy small plastic water bottles in Bali?

Press reports say a 2025 circular from Bali's governor bans single-use plastic bottled water under one litre. We could not find the official text, and the timing has been reported differently, so bring a refillable bottle and check the current rule locally.

What is the main safety risk when swimming with mantas at Nusa Penida?

The ocean itself: swell, surge and currents on a coast open to the Indian Ocean. Go only with an experienced local operator, wear fins, and stay on the boat if conditions or your confidence are not right.

Wildlife encounters are never guaranteed and never forced. Ocean Calling works only with vetted, ethical local operators, and every animal is free to approach, or not, entirely on its own terms.

Sources & further reading

Further reading on Ocean Calling: More from the journal · Wildlife & the law · See the retreats · Ocean Atlas

Ethical Manta Ray Swimming in Bali: A Nusa Penida Guide