Joao Vieira and Poilao

At the Bijagos' ocean edge, the Joao Vieira-Poilao marine park guards a phenomenon: Poilao island hosts one of the Atlantic's largest green turtle nesting colonies - thousands of females a season hauling onto a beach the Bijago hold sacred, a status that protected the island long before parks existed and still frames every landing. Visits run as boat expeditions with park and community arrangement: nesting nights under red-light protocol, days on the sister islands' empty sand and palm forest, and the archipelago's tidal world - dolphins in the channels, fish eagles overhead - as constant escort.

What's there

• The nesting nights - green turtles by the dozen under red light.
• Sacred Poilao - the island whose custom status saved its beach.
• The sister islands - Joao Vieira's palms and empty strands.
• The channel crossings - dolphins and tide-race birdlife en route.

When to go

July to October is the nesting heart - also the rains, which is the honest trade; seas and schedules negotiate daily. Arrangements go through park authorities and operators in Bissau or Bubaque, ahead.

Before you go

This is expedition travel: open-boat crossings, camp-or-basic lodging, and weather with the casting vote - margins and flexibility are required equipment. The island's sacred status sets rules beyond conservation's: follow both sets exactly. The reward is a world-class wildlife event with witnesses in single digits.

Nearby

Bubaque, Orango's hippos and the wider Bijagos maze.