When To Go · Destination Guide
Remote coral atolls where blue-water adventure meets serious conservation
Updated Mar 26, 2026 • 22 sources
When to go
The big pattern is simple.
Best overall window
Calmer seas, easier boat planning, and water often around 27°C to 29°C with stronger visibility.
Outside that window
Southeast trades bring wind, chop, and rougher exposed crossings, especially for less experienced seagoers.
Start with the overall answer, then switch only when scuba, freedive, snorkel, or topside timing changes the trip in a meaningful way.
The overall row stays visible so you can compare it against the currently selected scope.
| Scope | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall | Overall - Jan: Good | Overall - Feb: Good | Overall - Mar: Good | Overall - Apr: Best | Overall - May: Best | Overall - Jun: Tradeoffs | Overall - Jul: Tradeoffs | Overall - Aug: Tradeoffs | Overall - Sep: Tradeoffs | Overall - Oct: Best | Overall - Nov: Best | Overall - Dec: Good |
These do not replace the overall planner. Use them only if a specific animal or event is driving your trip dates.
Reef manta concentration around Alphonse and St Francois
Best for Snorkel, Scuba, Freedive
Oct to Dec
Manta work around the Alphonse Group has recorded especially strong sightings in lateyear months, making this the most exciting seasonal window for mantafocused snorkel or dive planning.
Green turtle nesting on Astove
Best for Topside, Snorkel, Scuba
Oct to Mar
Astove is one of the region's standout greenturtle nesting islands, and evening guided nesting viewings are among the most memorable nondiving experiences in the Outer Islands.
Hawksbill and green turtle activity on Desroches
Best for Topside, Snorkel
Oct to Mar
Desroches pairs yearround turtle sightings with its strongest nesting season in the warmer months, adding real wildlife value even for travelers who never scuba dive.
Humpback whale passage
Best for Snorkel, Topside
Jul to Oct
Bluewater trips around Desroches and Alphonse can intersect with humpback migration season, though sightings vary each year and should be treated as a bonus rather than a promise.
Turtle hatchlings and nesting beaches on Alphonse Group islands
Best for Topside
Jan to Mar
Alphonse and Bijoutier can produce the emotional payoff of hatchling moments after the main nesting season, especially if you join conservation staff rather than wandering beaches on your own.
Spinner dolphins and offshore cetaceans
Best for Snorkel, Topside
Year-round
Openocean Blue Safari sessions can produce spinner dolphins and other cetaceans in multiple seasons, especially around Alphonse and the more remote southern atolls.
Built from climate references, access rules, and destination operators. Wildlife timing and route flexibility can shift year to year.