Natural site · Cascais, Lisbon

Boca do Inferno

Boca do Inferno
Photo: Husond, CC BY-SA 3.0 via Wikimedia Commons

A collapsed sea cave on the cliffs just west of Cascais where Atlantic waves crash into a rocky chasm. It's a quick, free stop that's most dramatic when the sea is rough.

Updated October 18, 2026On day 4 of Lisbon, Sintra and the coast in 5 days

Visiting Boca do Inferno: what to know

Time to spend
20–30 minutes
Tickets
Free, open access
Best time
High tide or stormy days for bigger waves
Getting there
About a 20-minute walk west from Cascais centre

Lisbon itineraries with Boca do Inferno

Day 4 of Lisbon, Sintra and the coast in 5 days

The wild Atlantic coast

How Boca do Inferno fits into a day.
  1. 9:30Cabo da RocaSintra coast
  2. 12:00Praia do GuinchoCascais
  3. 15:00Boca do InfernoCascais
  4. 16:30Santa Marta LighthouseCascais
See all 5 days
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Boca do Inferno FAQs

How far is Boca do Inferno from Cascais?

It's roughly 2 km from the town centre, an easy walk along the coastal road.

When is Boca do Inferno most impressive?

On rough-sea days and at high tide, when waves surge into the cave. On calm days it's much quieter.

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