Alonnisos Marine Park

The marine park covers the sea around Alonnisos and a scatter of uninhabited islets to the north, and it is one of the largest protected marine areas in Europe. It exists mainly for the Mediterranean monk seal, a species that breeds in sea caves and does not tolerate disturbance, so the park is split into zones with different rules. Piperi, the core island, is closed to visitors entirely. Licensed day boats from Patitiri work the accessible parts, usually calling at Kyra Panagia with its monastery and grazing goats, the sheltered bay at Peristera, and one or two swim stops on the way. Dolphins turn up far more often than seals do. In Patitiri a small information point explains the conservation work.

What you actually see

• Kyra Panagia - an uninhabited island with a monastery, a sheltered anchorage and old terraces.
• The seal information point in Patitiri - a short, plain explanation of why the zones exist.
• Peristera bay - a long, quiet anchorage used as a swim stop on most trips.
• The boat crossing itself - open water, seabirds and regular dolphin sightings between islands.

When to go

Boats run roughly May to September and stop when the meltemi blows, which it does hardest in July and August. June and September give calmer seas and fewer people on the same boat. Trips are full days leaving in the morning, so plan nothing else. Book a day or two ahead in peak season; small operators sell out.

Honest expectations

Seal sightings are genuinely rare and no operator can promise one, so treat any as luck. The trips are long hours on a small boat, uncomfortable if you get seasick, and cancelled at short notice in wind. There is no visitor centre in the usual sense. Per-person prices add up quickly for a family, and the swim stops are the part most people remember.

Nearby

Alonnisos old village at Chora, the beaches of the east coast and the island of Skopelos.