Marstal is the working town to Ærøskøbing's museum piece. Its harbour is still active — fishing boats, a small shipyard, and the ferry to Rudkøbing on Langeland all share the basin — and the place has a more practical, less self-consciously pretty feel than its postcard neighbour. The 1841 stone breakwater was famously built by the townspeople themselves, hauling stones into the sea after the state refused to fund it.
The town is best appreciated on foot, wandering the streets behind the harbour where the captains' houses cluster. The Marstal Maritime Museum tells the story of Ærø's age of sail through ship models, navigation instruments, and figureheads. The 18th-century church on Kirkestræde has a ship hanging in the nave, as is the tradition in Danish maritime towns.