DiveJourneyDiveJourney

When To Go · Destination Guide

Outer Islands

Remote coral atolls where blue-water adventure meets serious conservation

Updated Mar 26, 2026 • 22 sources

View On Map

When to go

Best time to visit Outer Islands

The big pattern is simple.

Best overall window

April-May and October-November

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.

Choose your trip style

Start with the overall answer, then switch only when scuba, freedive, snorkel, or topside timing changes the trip in a meaningful way.

Month-by-month planner

The overall row stays visible so you can compare it against the currently selected scope.

BestGoodTradeoffsMore variable
ScopeJanFebMarAprMayJunJulAugSepOctNovDec
Overall
Wildlife goals and seasonal highlights

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

    JanFebMarAprMayJunJulAugSepOctNovDec

    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

    JanFebMarAprMayJunJulAugSepOctNovDec

    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

    JanFebMarAprMayJunJulAugSepOctNovDec

    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

    JanFebMarAprMayJunJulAugSepOctNovDec

    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

    JanFebMarAprMayJunJulAugSepOctNovDec

    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

    JanFebMarAprMayJunJulAugSepOctNovDec

    Openocean Blue Safari sessions can produce spinner dolphins and other cetaceans in multiple seasons, especially around Alphonse and the more remote southern atolls.

Always true for this destination
  • Use the transition months if your group mixes scuba, snorkeling, freedive training, and nondiver sightseeing.
Seasonal cautions
  • Dec to Mar: Warm, humid, and still very usable, with more rain interruptions but many pleasant sea days.
  • Jun to Sep: Southeast trades bring wind, chop, and rougher exposed crossings, especially for less experienced sea-goers.

Built from climate references, access rules, and destination operators. Wildlife timing and route flexibility can shift year to year.