Snorkeling in São Sebastião: Where to Go on the Islands and What to Bring
By MaresiasTur · · Updated on · 6 min read
Quick answer
To go snorkeling in São Sebastião, the simplest way is the islands of the South Coast, such as Ilha das Couves, Ilha dos Gatos, and As Ilhas, visited on the boat tours that leave from Boiçucanga. Bring your own mask and snorkel, and watch the animals without touching them.
Snorkeling in São Sebastião mostly happens around the South Coast islands. Ilha das Couves has a natural pool popular for floating with a mask, and Ilha dos Gatos is known as a diving spot with schools of fish. Both are part of the 3 Islands route, together with the island called As Ilhas, on the boat tours that leave from Praia de Boiçucanga, next to Maresias, with two stops for swimming.
This guide shows where to go, what typically shows up along the region's rocky shores, what to bring, and how to behave in the water so you don't hurt marine life or yourself.
Where to go snorkeling in São Sebastião?
The islands visited by MaresiasTur's tours appear on the list of São Sebastião diving spots recorded in the management plan of the North Coast Marine APA, a conservation unit managed by Fundação Florestal (Management Plan of the APAMLN).
- Ilha das Couves: has a natural pool recommended for snorkeling. The management plan describes the island as popular with divers and records the Toca da Velha there, a cave carved by the sea. It's not the Ilha das Couves in Ubatuba; the guide to São Sebastião's Ilha das Couves explains the difference.
- Ilha dos Gatos: a diving spot with schools of fish, about 1.5 km from Praia de Camburi. More details in the post about Ilha dos Gatos.
- As Ilhas: this is the name of an island, the third stop on the 3 Islands route. The management plan says it has two beaches suited for sunbathing and swimming and is popular for diving, SUP, and kayaking. The guide to As Ilhas covers what's known about it.
- Ilha do Montão de Trigo: has no beaches. The management plan lists Costão do Sudoeste and Ponta Negra as diving spots nearby.
- Calhetas: the boat route to Ilhabela makes a diving stop at Calhetas on the way back.
Which tours have a snorkeling stop?
| Tour | Stops | Flotation equipment and mask |
|---|---|---|
| Private Boat Tour – The 3 Islands (about 3 h) | Route by Ilha das Couves, Ilha dos Gatos, and As Ilhas, with two stops for swimming | Mask is not listed among the included items |
| Shared Boat Tour – The 3 Islands (about 3 h) | Two stops for swimming and snorkeling | Pool noodles included; mask not listed |
| Shared Boat Tour – Montão + The 3 Islands (about 4 h, leaves from Praia de Maresias) | Stops for swimming | Diving mask and pool noodles not included |
| Private Boat Tour – Ilhabela Route (about 6 h) | Diving stop at Calhetas on the way back | Mask is not listed among the included items |
The private boat gives more freedom: the boat is only for your group, up to 14 people, departing in the morning, afternoon, or at sunset. The price is per boat, from R$ 1,450 (up to 2 people) to R$ 2,850 (up to 14), reference prices from September 2026; the updated price is on the page for the private boat tour to the 3 Islands of the South Coast. Couples and small families may prefer the shared boat tour, charged per person.
Which fish and animals show up along the rocky shores?
There is no fish census done specifically at Couves or Gatos, and the management plan itself acknowledges this gap. The best available picture comes from nearby rocky shores: a study published in 2012 in the scientific journal Neotropical Ichthyology recorded 106 fish species in visual censuses along the São Sebastião Channel shores and islands of Ilhabela (Gibran and Moura, 2012, SciELO).
The species seen most often in that survey were the sargentinho, the donzela, and the butterflyfish, plus Haemulon aurolineatum, the most abundant. The APA's management plan also lists, along the region's rocky shores, salemas, sargos-de-beiço, badejos, garoupas, and vermelhos. This helps you know what to look for, but doesn't guarantee what will show up at each stop.
What about the turtles? The North Coast Marine APA hosts a considerable number of young green sea turtles, which feed mainly on algae, and there are records of them feeding in São Sebastião. The species is endangered. Spotting one is a matter of luck, not a guaranteed part of the tour.
How should you behave in the water while snorkeling?
No specific Brazilian regulation was found about touching fish while snorkeling in the APA, but best practices for watching marine life are clear. The United States fisheries agency advises not touching, chasing, or feeding marine animals, and notes that the mucus covering fish protects them from infections (NOAA Fisheries).
- Look without touching: fish, turtles, and everything that lives attached to the rocks.
- Don't feed the fish, not even with snack leftovers.
- Don't step on or lean against the submerged rocky shore; floating with a pool noodle or life vest helps.
- If a turtle appears, keep your distance and don't try to hold it.
- Bring all your trash back to the boat.
The management plan specifically highlights the role of divers and snorkelers in showing the care needed not to disturb the animals and the environment where they live.
What to bring for snorkeling on the islands?
- Your own mask and snorkel, well fitted to your face. The mask isn't listed among the tours' included items, and on the shared boat to Montão it's explicitly not included.
- Swimsuit under your clothes and a towel.
- Sunscreen and a long-sleeve shirt, since your back stays in the sun while floating face-down.
- Water and a light snack, since food and drinks are not included.
- A dry bag for your phone and documents.
The full list is in what to bring for a boat tour, hike, and rappelling. Before booking, it's worth checking the tide table for São Sebastião: with an unfavorable tide, the shared tour offers rescheduling or a full refund.
And what about going beyond snorkeling?
In snorkeling, you stay at the surface and breathe through the tube. To actually go down, the option is to try scuba diving at Ilha das Cabras, in Ilhabela: it requires no course, has an average depth of 6 meters and 30 to 50 minutes underwater with a PADI instructor, and includes full equipment and individual insurance. The minimum age is 10, with parental consent. The post on trying scuba diving at Ilha das Cabras explains how it works.
Frequently asked questions
- Where can you go snorkeling in São Sebastião?
- On the South Coast islands, such as Ilha das Couves, which has a natural pool, and Ilha dos Gatos, a diving spot with schools of fish. Both are part of the 3 Islands route, together with As Ilhas, on the boat tours that leave from Praia de Boiçucanga, with two stops for swimming.
- Is the snorkel mask included in the tour?
- It isn't listed among the included items. The shared boat to the 3 Islands includes pool noodles, and on the shared boat to Montão de Trigo, the mask and floats are not included. It's best to bring your own.
- Can you see a turtle while snorkeling in São Sebastião?
- It can happen: young green sea turtles frequent the North Coast Marine APA and have been recorded feeding in São Sebastião. It's not guaranteed, and if one appears, best practice is to observe from a distance without touching it.
- Can someone who isn't a strong swimmer go snorkeling on the islands?
- Yes, they can enjoy the stops with care, using flotation items and letting the crew know before the tour. The tours have a licensed sailor and safety items, and the shared tour includes pool noodles.
- Are snorkeling and trying scuba diving the same thing?
- No. In snorkeling, you float on the surface with a mask and tube. In the try-dive, done at Ilha das Cabras, in Ilhabela, you go down an average of 6 meters with a tank and a PADI instructor, with no course required.
