Skiathos Port has served as the gateway to the Northern Sporades since the fourth century BCE, when Athenian triremes used the natural harbour as a staging point for campaigns in the Aegean. Today the port authority manages over two hundred daily departures during summer months, the majority bound for Skopelos, eleven nautical miles northeast across a strait that rarely exceeds twenty metres in depth. The island-hopping corridor between these two landmasses remains one of the busiest short-haul ferry routes in Greece, with conventional ferries, hydrofoils, and private excursion vessels sharing the same navigational channel. Skopelos owes its modern tourism profile to a single film location decision in 2007, when production designers for Mamma Mia selected the cliffside chapel of Agios Ioannis sto Kastri as the setting for a fictional wedding. The chapel, reached by two hundred and ten steps carved into volcanic rock, had been a minor pilgrimage site since the seventeenth century. After the film's release, daily visitor numbers rose from fewer than fifty to more than three thousand during peak weeks in July and August. Local authorities installed handrails and widened the original footpath, but the structure itself—a single-nave building measuring four metres by six—remains unchanged. Most skiathos to skopelos day trip by boat itineraries include stops at Glysteri, a crescent beach on the island's northwest coast where Aleppo pines grow to within three metres of the tideline, and Panormos, a double bay separated by a limestone spit that provides shelter from the meltemi winds that sweep south from the Thracian Sea between June and September. The crossing itself takes between forty and seventy minutes depending on vessel type and sea state. Conventional ferries follow a direct route; excursion boats often detour to pass Tsougria, an uninhabited islet one kilometre offshore, where monk seals were sighted as recently as May 2025. Water temperature in the channel averages twenty-three degrees Celsius in summer, with visibility exceeding fifteen metres on windless days. The strait's shallow topography creates pronounced tidal currents near the Skopelos harbour entrance, requiring ferry captains to adjust approach angles during spring tides. Departures from Skiathos Port operate under a coordinated schedule managed by the Hellenic Coast Guard, with vessels assigned to specific berths along the western quay. The port authority building, a two-storey structure dating from 1964, houses ticket counters for conventional ferry services, but most island-hopping cruises use independent booking systems. The harbour basin, dredged to a depth of eight metres in 2019, accommodates vessels displacing up to five hundred tonnes.