Vietnam · South Central Coast

Nha Trang

Best visibility commonly falls outside the heavier rainy and storm season.

Nha Trang is Vietnam's main diving city — easy boat access to a small marine park, mostly soft coral and macro, with mild current. Recovering from years of overfishing; biodiversity is improving but not at regional-best level.

Good season

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

March–September is best; October–February brings rough seas from the northeast monsoon.

Trip duration

2–3 days as part of a longer Vietnam trip.

Dive style

Boat day-trips; mild current; mostly shallow.

Dive level

Open Water; popular for certifications.

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 · 1.1 °C-week heat dose

What to expect on a dive

Heavily impacted by 2024 thermal stress. Operator-led restoration projects ongoing.

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: 1.1 °C-wk
  • SST anomaly: +0.7 °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

  • dive-school over-capacity
  • warming
  • coral disease

2 Green Fins-verified operators known at this location.

What you can do

Hon Mun MPA was Vietnam's first MPA. Koh Tao reefs are heavily loaded with training divers — picking ecology-focused dive schools helps reduce shallow-reef impact.

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.

Pollution & water-quality

What divers should know
  • Heavy thermal stress + coral mortality

    SEVERE

    Since 2024

    Severe 2024 bleaching event triggered closure of large parts of Hon Mun MPA to diving for restoration work. Check current status with operators.

High microplastics

What this means for your trip

Hon Mun MPA access has been restricted since 2024 — verify operator permits before booking. Consider Phu Quoc as an alternative.

Dive sites here

1 curated

Gear

What to bring

Basic kit

What divers say

Don't come to Nha Trang for the diving — come for everything else and dive while you're here.
Honest dive shop owner