Dalarö Fort, Sea fort in Haninge Municipality, Sweden.

Dalarö Fort is a stone fortification positioned strategically in the Stockholm archipelago, featuring defensive walls and military architectural elements from the 17th century. The structure demonstrates typical characteristics of a coastal defense installation with walls designed specifically to protect against maritime threats.

A first timber-and-earth redoubt was built on Skansberget in 1623 and decayed through neglect. The present fort was begun in 1656 by Johan Peter Kirstenius under Charles X Gustav to protect ships anchored at Dalarö. Erik Dahlbergh planned a modernization in 1683, but work under that scheme only started in 1698; the fort was defensible by 1724 and its tower received its roof in 1753. It was never in combat, was bypassed by Russian forces in 1719, and left the permanent defence on 28 March 1854.

The name skans refers to a small fortification, and the site is owned and managed by the National Property Board of Sweden. Since 1935 it has been a listed building, and today its rooms are rented out as a function hall for weddings and private parties. The last fortification commander was Captain Thorbjörn Morén.

Dalarö Fort stands on Stockskärsholmen, a small island just south of Dalarö in the Stockholm archipelago, and is reached by a short crossing from the Dalarö side rather than by long boat connections from the city. The building is owned and managed by Statens fastighetsverk and is used for private functions such as weddings, so visitors should check access before crossing.

The fort never saw combat: Russian forces bypassed it during the raids of 1719. Its last fortification commander was Captain Thorbjörn Morén, and it left the permanent defence on 28 March 1854. Since 1935 it has been a listed building, now owned and managed by the National Property Board.