China · Hainan

Sanya

Warmer water and calmer weather usually dominate outside the coolest winter spells.

Sanya on Hainan Island is mainland China's most developed dive destination — mostly shallow reef and resort-style diving, popular for domestic certifications. Not internationally competitive, but improving.

Good season

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

March–November; typhoon risk July–September.

Trip duration

2–3 nights as part of a domestic China trip.

Dive style

Shallow boat diving; very mild current.

Dive level

Beginner; primarily a cert market.

Reef health

What you’ll actually find
Mixed

Some loss since the 2010s, but the reef still has plenty to dive. Pick depth and shoulder-season carefully.

Coral reef health

How is this calculated?
A decade ago
Survey 2014
33%
Today
Survey 2024
29%

On current trend, no live coral by ~2097. Losing about 0.4% cover per year — roughly 73 years of reef left to see if nothing changes.

Heat stress right now

Watch

Mild warmth. Worth watching — no bleaching yet.

NOAA Coral Reef Watch · updated May 2026 · 0.2 °C-week heat dose

What to expect on a dive

Limited recent independent monitoring. Reef cover is modest; trips are popular for proximity to mainland China.

Sources, methodology, and the raw numbers

Raw observed numbers

  • Coral cover: 29% (survey Sep 2024, Department of Marine and Coastal Resources Thailand survey)
  • Bleached: 14%
  • Recent mortality: 5%
  • Gulf of Thailand — observed condition reflects the declining regional pattern.

Raw thermal numbers

  • NOAA CRW alert level: Watch
  • Degree Heating Weeks: 0.2 °C-wk
  • SST anomaly: +1.4 °C

How we summarise this

Observed coral cover, bleaching, and mortality come from named in-situ surveys with a stated date and method — they describe one snapshot of one reef and do not extrapolate to neighbouring sites. Current thermal stress is satellite-derived from NOAA Coral Reef Watch at ~5 km resolution; it indicates risk, not observed coral damage. We deliberately separate observed condition, current thermal stress, and projection — and we never publish a projection without a documented model and uncertainty.

Sources

Reef condition changes year to year. If you visit, consider supporting responsible-travel and conservation operators on the ground.

Pressure on this reef

Protection · fishing · what you can do

Protected-area status

Multi-use MPA

Inside a designated MPA that permits regulated fishing and other uses. Worth checking which zones at this location are no-take.

Fishing pressure

Moderate fishing pressure

Dominant pressures

  • coastal development
  • fisheries

1 Green Fins-verified operator known at this location.

What you can do

Subtropical reefs with limited formal MPA coverage. Choose operators that pay into local fisher cooperatives.

Protection status sourced from Protected Planet / WDPA and refined with Marine Protection Atlas. Fishing pressure proxy is Global Fishing Watch AIS data. See the methodology for what these sources can and can’t prove.

Dive sites here

1 curated

Gear

What to bring

Basic kit

What divers say

If you're already in Hainan, dive. If you're picking a destination, fly somewhere else.
Expat diver