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Bajo Alcyone

Cocos Island, Costa Rica · 25–40m · advanced · exposed

Seamount off Cocos Island, 500km from the mainland, where hammerheads school in the current above the pinnacle.

Conditions today

Retrieved · refreshed hourly

marginal

Marginal — 1.3m effective waves in the morning window.

Limiting factor: waves

Wave height
1.3–1.4m
Wave period
8.8–10.6s
Wind chop
0m
Sea temp
29.8–29.9°C

Ranges span today's hours. Wave height here is the raw sea state — the rating scales it for how exposed the site is. Exposed — open water with nothing to block the swell, so it is scored at full height.

Next few days

  • TodayMarginal — 1.3m effective waves in the morning window.marginal
  • FridayMarginal — 1.3m effective waves in the morning window.marginal
  • SaturdayMarginal — 1.3m effective waves in the morning window.marginal

Each day is scored over its morning dive window, the same as today's rating.

Dive briefing

AI-generated

Conditions are marginal today at Bajo Alcyone. A swell of 1.3–1.4 m is forecast, with wave periods between 8.8 and 10.6 seconds. The site's exposure means you need to be comfortable in rougher water. Sea temperature sits at 29.8–29.9°C. This is an advanced dive on a pinnacle where you'll work in current; marginal conditions add another layer of demand, so come prepared for challenging water.

Divers commonly log whitetip reef sharks here, along with Cocos wrasse, Mexican hogfish, guineafowl puffer, blue-and-gold snapper, and bluefin trevally. Leather bass and Galápagos gregory are also often recorded. The schooling hammerheads this site is known for are a highlight when conditions align — keep your eyes on the blue above the pinnacle.

Written by Claude (claude-haiku-4-5-20251001) from the rating, forecast, and sightings on this page — it has no other source and cannot look anything up. Treat it as a summary, not as local knowledge.

Commonly seen here

Most-recorded species near this site, ranked by research-grade iNaturalist sightings from divers, snorkelers, and naturalists.

Species come from iNaturalist — research-grade sightings logged by divers, snorkelers, and naturalists nearby. The ranking reflects what people photograph most, not guaranteed abundance. Ask a local operator what's actually being seen. Species names link to iNaturalist for range maps, seasonality and more photos. Photos by iNaturalist contributors under Creative Commons licences — individual credit on hover.