South America · Brazil
Arvoredo Marine Reserve
Granite reefs where tropical and temperate species overlap
Photo: Matheus Hobold Sovernigo · CC BY-SA 4.0
The Arvoredo Biological Reserve protects a group of granite islands an hour by boat from Florianópolis, in the subtropical transition zone where tropical and temperate species overlap. The reserve itself is closed to recreational diving; operators work the boulder slopes along the southern shore of Ilha do Arvoredo, outside the reserve boundary, with sea fans, large groupers and shoals of horse-eye jacks. Southern right whales pass offshore between July and November, watched from the boat rather than dived with.
About diving in Arvoredo Marine Reserve
Everything here is a boat day and the boat leaves early. Operators run out from Bombinhas and from the beaches at the north end of Florianópolis, on half- or full-day trips built around two dives, with the surface interval anchored in the lee of an island. Access is controlled rather than open: you book through an authorised centre and dive where its authorisation allows, so this is not a coast where you turn up at the harbour in the morning and negotiate a boat.
The islands are granite domes, which underwater reads as big rounded boulders stacked into slopes and short vertical faces, with sand channels running between them. The sheltered northern ground is gentle and stays divable in most conditions, so it absorbs the bulk of the traffic and is the fallback whenever the southerlies are up; the more exposed sites are deeper and want a calm day. The islands have been protected since 1990, and divers tend to notice it first in the size of the resident groupers.
Because wind decides whether the boats run at all, most people build slack into the plan. Booking a two- or three-day window instead of a single fixed date is the standard local approach, and centres will usually roll a cancelled trip forward. The reserve suits divers content with structure, big resident fish and cold-water invertebrates rather than coral colour, and it works as a two-day addition to a trip already heading for Florianópolis or Bombinhas. Bring more thermal protection than the latitude suggests, because the water at depth runs colder than the beach weather implies.
Best time to dive Arvoredo Marine Reserve
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Season | Prime | Prime | Prime | Good | Fair | Fair | Fair | Fair | Good | Good | Good | Prime |
| Sea surface | 26°C79°F | 27°C81°F | 26°C79°F | 24°C75°F | 22°C72°F | 20°C68°F | 18°C64°F | 18°C64°F | 19°C66°F | 21°C70°F | 23°C73°F | 25°C77°F |
| Daytime high | 28°C82°F | 28°C82°F | 28°C82°F | 26°C79°F | 24°C75°F | 22°C72°F | 21°C70°F | 21°C70°F | 22°C72°F | 24°C75°F | 25°C77°F | 28°C82°F |
| Rain | 180 mm7.1 in | 133 mm5.2 in | 125 mm4.9 in | 84 mm3.3 in | 115 mm4.5 in | 111 mm4.4 in | 93 mm3.7 in | 92 mm3.6 in | 118 mm4.6 in | 135 mm5.3 in | 109 mm4.3 in | 125 mm4.9 in |
| Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|
| Prime | Prime | Prime | Good | Fair | Fair |
| Sea surface | |||||
| 26°C79°F | 27°C81°F | 26°C79°F | 24°C75°F | 22°C72°F | 20°C68°F |
| Daytime high | |||||
| 28°C82°F | 28°C82°F | 28°C82°F | 26°C79°F | 24°C75°F | 22°C72°F |
| Rain | |||||
| 180 mm7.1 in | 133 mm5.2 in | 125 mm4.9 in | 84 mm3.3 in | 115 mm4.5 in | 111 mm4.4 in |
| Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|
| Fair | Fair | Good | Good | Good | Prime |
| Sea surface | |||||
| 18°C64°F | 18°C64°F | 19°C66°F | 21°C70°F | 23°C73°F | 25°C77°F |
| Daytime high | |||||
| 21°C70°F | 21°C70°F | 22°C72°F | 24°C75°F | 25°C77°F | 28°C82°F |
| Rain | |||||
| 93 mm3.7 in | 92 mm3.6 in | 118 mm4.6 in | 135 mm5.3 in | 109 mm4.3 in | 125 mm4.9 in |
2011–2025 averages. Sea surface: NOAA Coral Reef Watch, measured at the surface, so deeper water can run colder. Daytime high and rain: NASA POWER.
Dec–Mar brings the warmest, clearest water and the calmest crossings; winter southerlies frequently cancel boats and drop the temperature to 16°C.
Best months: January, February, March, December
Arvoredo water temperature and weather by month
The sea surface runs from 18 °C (64 °F) in July to 27 °C (81 °F) in February. It is 24 °C (75 °F) or warmer from December to April. Rain falls through the year, about 120 mm (4.7 in) a month on average, with January the wettest. Daytime highs reach 28 °C (82 °F) in February and drop to 21 °C (70 °F) in July. The coldest water here is about 16 °C (61 °F), so pack a 7 mm suit with a hood, or a semi-dry.
Dive types & marine life
Groupers are the dependable sighting, holding on the same boulders year-round alongside turtles, stingrays over the sand channels, octopus and nudibranchs in the rock. Schooling fish are best in the warm, clear December-to-March window. Southern right whales pass offshore between July and November, seen from the boat rather than dived with, in the months when wind most often cancels trips.
- Reef
- Wall
- Wreck
- Night
- Sea turtles
- Groupers
- Stingrays
- Octopus & cuttlefish
- Reef fish swarms
- Whales
- Nudibranchs
Best dive sites in Arvoredo Marine Reserve
Rock passages on the bottom and a cave that opens to the surface
Wreckage of the Granada scattered across the cove floor
A two-chamber cave with large groupers inside it
Rancho Norte
The reserve's most-dived sector, sheltered boulder slope to 20 m.
Ilha Deserta
Outer island with the clearest water and schooling jacks.
Ilha das Galés
Rock walls and swim-throughs just outside the reserve boundary.
Naufrágio Lily
Cargo wreck near Florianópolis, an alternative when the reserve is closed.
How to get to Arvoredo Marine Reserve
Florianópolis has the nearest airport. Divers base either at the island's north end, around Canasvieiras and Jurerê, or in Bombinhas on the mainland, which has the shortest crossing to Ilha do Arvoredo. Everything is dived from day boats booked through authorised local operators; there is no shore access to the reserve and no liveaboard.
Photos from Arvoredo Marine Reserve
Leonardo Manuel Baez Schuh · CC BY-SA 4.0
Dive videos
Mergulho na Ilha do Arvoredo - Florianopolis (SC)- Brasil 2018 · Rafic Bittencourt on YouTube
Ep42. Mergulho em Reserva de Arvoredo, Santa Catarina. Profundo Scuba Diving, turismo e aventura. · Aventuras Produções on YouTube
Photo credits
- Aerial view of turquoise water meeting the granite, forested coastline of Arvoredo Marine Reserve by Matheus Hobold Sovernigo, CC BY-SA 4.0, via Wikimedia Commons
- Smoothtail spiny lobster sheltering among rocks on a reef near Arvoredo, Brazil by Leonardo Manuel Baez Schuh, CC BY-SA 4.0, via Wikimedia Commons
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