Myanmar (Burma) · Indian Ocean

Best time to dive Mergui Archipelago

Liveaboard-only, from Ranong (Thailand) via Kawthaung. Boats run roughly November to early May and stop for the June–September monsoon; mantas and the odd whale shark peak February–April, especially at Black Rock.

Peak season: January–April

Best upcoming months:7.6March 2027 7.5April 2027 7.3February 2027

Overall diving, month by month

Balanced scoring · forecasts include the 2026/27 El Niño outlook

Confidence: Nov medium · Dec medium · Jan medium · Feb low · Mar low · Apr low · May low · Jun low · Jul low · Aug low · Sep low · Oct low · Nov low · Dec low

What's good when

Each attribute scored 0–10 for every month

	Nov2026	Dec	Jan2027	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Pelagic & big animals	7	7	7	8	9	9	8	7	7	7	7	7	7	7
Macro life	7	7	7	7	7	7	7	7	7	7	7	7	7	7
Coral & reef health	5	4	5	5	3	3	3	3	4	4	4	4	4	4
Visibility	6	7	7	7	7	7	6	6	6	6	6	6	6	7
Water temperature	10	10	10	10	10	9	9	10	10	10	10	10	10	10
Weather & sea state	8	9	9	9	9	8	6	4	4	4	4	6	8	9
Operations & access	8	9	9	9	9	9	4	0	0	0	0	3	8	9

Climate outlook

How this year's forecast differs from a typical year

Water temperature +0.7 °C · Andaman Sea warms in the months after an El Niño peak (Nov 2026 – July 2027)
Coral & reef health -1 · Reefs still recovering from post–El Niño bleaching (Nov 2026 – December 2027)
Coral & reef health -2.3 · Post–El Niño bleaching risk, as in 2010 when dive sites were closed (Mar 2027 – June 2027)

Water temperature & visibility

Month	Water	Visibility
November 2026	28.8 °C (84 °F)	15–20 m
December 2026	28.4 °C (83 °F)	15–25 m
January 2027	28.5 °C (83 °F)	15–25 m
February 2027	28.6 °C (83 °F)	15–25 m
March 2027	29.1 °C (84 °F)	15–25 m
April 2027	30.2 °C (86 °F)	15–25 m
May 2027	30.1 °C (86 °F)	10–20 m
June 2027	29.5 °C (85 °F)	10–20 m
July 2027	28.9 °C (84 °F)	10–20 m
August 2027	28.8 °C (84 °F)	10–20 m
September 2027	28.7 °C (84 °F)	10–20 m
October 2027	28.6 °C (83 °F)	10–20 m
November 2027	28.5 °C (83 °F)	15–20 m
December 2027	28.0 °C (82 °F)	15–25 m

Marine life calendar

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
manta ray		●	Peak	Peak	Peak	●
whale shark			●	●
frogfish	●	●	●	●	●	●	●	●	●	●	●	●
nurse shark	●	●	●	●	●	●	●	●	●	●	●	●
seahorse	●	●	●	●	●	●	●	●	●	●	●	●

Peak = best odds · ● = regularly seen · blank = unlikely. Calendar months, every year.

About the diving

Difficulty: Intermediate
Current strength: 4 / 5
Luxury level: 4 / 5
Typical depth: 10–30 m
Max depth of interest: 40 m
Dive styles: Liveaboard
Suggested certification: Advanced Open Water
Nearest airport: HKT
Snorkelling: Limited
Known for: manta ray, whale shark, nurse shark, frogfish, seahorse

Famous sites: Black Rock · Western Rocky · Shark Cave · North Twin

Season notes & sources

Liveaboard-only, from Ranong (Thailand) via Kawthaung. Boats run roughly November to early May and stop for the June–September monsoon; mantas and the odd whale shark peak February–April, especially at Black Rock.
Reef condition is very uneven: some remote northern reefs have high hard-coral cover, but blast fishing has stripped walls near fishing communities and at several named island groups.
Still reached from Thailand despite the instability since the 2021 coup; check current travel advisories and Myanmar visa and park-fee rules before booking.