Guided visits to the ornithological reserve at the eastern end of the bay, led by the naturalist guides of the Maison de la Nature du Bassin d'Arcachon. The walk covers about five kilometres of the reserve's trails, and binoculars are handed out at the start.
The difference a guide makes here is not the walking — the trails are open to anyone with a ticket — but knowing what you are looking at. Which of the hundreds of birds on the lagoon in front of you is worth the telescope, and why it is here this month rather than another.
Morning visits are around €12, evening ones €13.50, both with reductions for children, students and job seekers, and the ticket covers the reserve all day. Booking is required.