← All sites

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 — 0.4m effective waves made worse by short-period chop.

Limiting factor: period

Wave height
0.7–0.8m
Wave period
4.3–4.6s
Wind chop
0.4–0.5m
Sea temp
29.9–30.2°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 — 0.4m effective waves made worse by short-period chop.marginal
  • SundayExcellent — calm morning with 0.3m effective waves.excellent
  • MondayExcellent — calm morning with 0.3m 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. The rating reflects short-period chop making surface conditions choppy despite modest raw wave heights of 0.7–0.8m. You'll need advanced certification for the deep descent; plan your air carefully for the 40m bottom. Water temperature sits at 29.9–30.2°C, so thermal protection is minimal. This is a sheltered site, which helps, but the sea state will make entry and exit less straightforward than usual.

Divers commonly log stoplight parrotfish, Atlantic blue tangs, and angelfish throughout the hole. Nurse sharks and Caribbean reef sharks are often recorded here as well. Work with your guide on positioning and buoyancy before descending into the darker water, and stay alert to your team and surroundings during the dive.

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.