9. Scalloped hammerhead
sharks are the undisputed
stars of the show at Cocos
Island
PRACTICALITIES
COSTA RICA
Cocos Island
By ALLISON VITSKY SALLMON
What keeps Cocos Island fanatics returning year after year?
It certainly isn’t the potential for relaxation, as getting there
involves a gruelling 36-hour crossing from mainland Costa
Rica. And it probably isn’t the likelihood of idyllic diving
conditions, since rainy skies, choppy seas, particulate-filled
water, and current-ripped sites are more common than not. It
isn’t even the gregarious marble rays, the squadrons of eagle
rays, or the massive schools of jacks, though this variety of
marine life is present on every dive.
Cocos Island’s main attraction is, of course, sharks. Howard
Hall once described Cocos as having “more sharks per cubic
metre of salt water than anywhere in the world”, and he
wasn’t kidding. Reef, nurse, silky, Galápagos, tiger, and whale
sharks are a big part of the lineup, but the addicts are here for
the schools of scalloped hammerheads. This island is perhaps
the best place on Earth for near-guaranteed interactions with
these bizarre creatures, which swarm gracefully overhead as
divers grip the jagged, rocky reef.
WHEN
January to June is the “dry”
season, offering more sun and
better potential for calm seas.
The cool upwelling of the Julyto-December “rainy” season
provides ideal metabolic conditions
for sharks and is considered the
optimal time for shark interactions.
Divers should be aware of the
potential for extreme thermoclines
with cool (low- to mid-20s °C) water
temperatures, changing visibility,
and very strong currents.
HOW
Cocos Island is only accessible by
liveaboard, all of which operate out
of mainla