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Great Blue Hole

Lighthouse Reef, Belize · 12–40m · advanced · sheltered

The iconic collapsed sinkhole — a deep, dark descent past stalactites at 40m, inside the atoll lagoon.

Conditions today

Retrieved · refreshed hourly

marginal

Marginal — 0.6m effective waves made worse by short-period chop.

Limiting factor: period

Wave height
0.9–1.3m
Wave period
5.1–5.6s
Wind chop
0.3–1.1m
Sea temp
28.8–29.1°C

Ranges span today's hours. Wave height here is the raw sea state — the rating scales it for how exposed the site is. Sheltered — reef or lagoon protection, so swell is scored at half its open-water height.

Next few days

  • TodayMarginal — 0.6m effective waves made worse by short-period chop.marginal
  • FridayMarginal — 0.4m effective waves made worse by short-period chop.marginal
  • SaturdayExcellent — calm morning with 0.4m effective waves.excellent

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

Dive briefing

AI-generated

Conditions are marginal today. Short-period chop is working against you — the rating reflects 0.6m effective wave height made worse by that choppy sea state. Raw wave heights reach 0.9 to 1.3m, with periods between 5.1 and 5.6 seconds. Water temperature sits at 28.8 to 29.1°C. This is an advanced site, and you'll want solid buoyancy control for the descent past the stalactites at 40m.

Divers commonly log nurse sharks and Caribbean reef sharks here, along with stoplight parrotfish, Atlantic blue tangs, angelfish, and Caribbean bluehead wrasse. Caribbean land hermit crabs are often recorded as well. The site's sheltered position in the atoll lagoon helps, but today's conditions remain choppy. Marginal doesn't mean undiveable, but it means the day will work harder than you'd prefer.

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.

Other sites nearby

Within 25km, closest first — usually the same day's boat.