By boat and by ferry
Half of Skiathos has no road on it, and the neighbouring islands are a short hop. Everything here leaves from one of the two harbours in town — and getting the two harbours the right way round is the first thing to learn.
The Bourtzi peninsula splits the Skiathos Town waterfront in two, and the two sides do different jobs.
The one to do if you only do one.
A full day from the Old Port, typically running clockwise: the sea caves — Skotini the dark cave and Galazia the blue one, both enterable only by small boat — then Kastro, the abandoned medieval capital seen from the water with a small beach below, then Lalaria for an hour or two, sometimes finishing at Tsougria. Around €25–35 per person for a group trip; older listings quoting €15 are out of date.
This is the only way to see the northern half of the island, which has no road.
The small island just offshore to the south-east, with several sandy beaches and a summer-only canteen. Taxi boats run from the Old Port roughly hourly from 10:00, returning on the half-hour until early evening, with a crossing of 15–20 minutes. Around €10–12 return, though sources differ on the fare and the departure point.
It is a separate island, so it is genuinely boat-access only — a half-day rather than an expedition.
The near neighbour, and the standard island day trip. Ferries and high-speed craft run from the New Port, landing at either Glossa/Loutraki at the northern end or Skopelos Town — which one matters, because they are a long way apart.
Skopelos is also where most of Mamma Mia was actually filmed, including the hilltop chapel of Agios Ioannis Kastri that stands in for the wedding scene. Only two scenes were shot on Skiathos itself.
Beyond Skopelos, Alonnisos is the gateway to the National Marine Park of Alonnisos and the Northern Sporades, the largest marine protected area in Europe and a refuge for the Mediterranean monk seal. We have not researched it to the standard of the rest of this site and would rather say so than pad the page.
The round-island trip from the Old Port: the Skotini and Galazia sea caves, Kastro from the water, and a stop at Lalaria beach, typically six to eight hours for around €25–35 per person. It is the only way to see the northern half of the island, which has no road.
The Old Port, west of the Bourtzi peninsula — that is where the excursion caiques and water taxis moor. The New Port on the eastern side is for ferries and hydrofoils to the mainland and the other islands.
Yes — ferries and high-speed craft run from the New Port. Check which port you land at, because vessels serve both Glossa/Loutraki at the northern end and Skopelos Town, and they are a long way apart. Skopelos is also where most of Mamma Mia was filmed, including the hilltop wedding chapel.
By boat only — there is no road and no path down the cliffs. It is a standard stop on the round-island trips from the Old Port, usually combined with the sea caves and Kastro. In a strong meltemi the boats cannot land, so book early in your stay.