The Hafnarborg Collection now counts around 1,600 works of art. Sverrir Magnússon and his wife, Ingibjörg Sigurjónsdóttir, laid the foundations of the museum with a generous donation of artworks in 1983. The painter Eiríkur Smith also made a large contribution of art in 1990, as did Elías B. Halldórsson and Gunnar Hjaltson, who both donated a number of their own graphic works. Many other artists and individuals have contributed to the collection as well and Hafnarborg seeks to purchase works in accordance with the museum’s policy and budget. Selections from the Collection are exhibited on a regular basis.

The artworks donated by Sverrir and Ingibjörg formed the basis of the Hafnarborg Collection, counting nearly 200 works by pioneers of Icelandic art, such as Kjarval, Nína Tryggvadóttir, Jóhann Briem and Júlíana Sveinsdóttir. Sverrir himself began collecting art around the time of the Great Depression, when he acquired a watercolour painting by Ólafur Túbals. This was the starting point, but the collection grew piece by piece, as Sverrir kept a keen eye on art exhibitions, regularly purchasing works and adding to the collection. Looking at the Founding Collection, most of the works are traditional landscapes, town scenes of Hafnarfjörður and still life paintings, perhaps reflecting the taste of the bourgeoisie at a certain period in Icelandic history.

As stated above, the Hafnarborg Collection now counts over 1,600 works of art – paintings, three-dimensional pieces, videos, and outdoor works. Since this year, the Art Council of Hafnarborg has an acquisition budget of three and a half million ISK. Proposals regarding which works to purchase are made by the Director, often in relation to exhibitions, as it is deemed of importance that the Collection reflect the exhibition programme of the museum. All proposed acquisitions, donations and purchases, must be approved by the Art Council of Hafnarborg before being accepted to the Collection. The museum does not accept donations with restrictions or requirements.

In Hafnarfjörður, a collection of public artworks can be seen, related to the history of the town, its population and the harbour, both memorials and monuments, in addition to abstract sculptures and works inspired by nature. A number of the works are located either in the heart of Hafnarfjörður or by the harbour, though many are to be found in the sculpture garden at Víðistaðatún Park, in Hellisgerði Park or around the retirement home of Sólvangur. Among notable artists represented in the public spaces of Hafnarfjörður are Ásmundur Sveinsson, Gestur Þorgrímsson, Einar Már Guðvarðarson, Sverrir Ólafsson, Hallsteinn Sigurðsson and Steinunn Þórarinsdóttir, as well as various foreign artists connected to the town. An overview of public art in Hafnarfjörður can be found at utilistaverk.hafnarborg.is.

The Hafnarborg Collection is listed in the museum collection database Sarpur. The operating company of Sarpur is the owner of the software, whereas the associated museums own the data that they enter into the database. This database itself is centralized and every precaution is taken in its management, whether it be in regards to copying or updating the system. In 2020, Hafnarborg signed a contract with Myndstef concerning the digital publication of images of the museum collection in electronic databases, thus allowing the museum to publish images online of all the works listed in Sarpur. Consequently, steps were taken to make the images, which were previously unpublished, accessible to the public, and museum workers strive to improve upon this, as well as all other information therein. The database is open to the public at sarpur.is.