Following his swimming career, Birgir took up basketball with Bolungarvík in 1990 at the age of 21. After one season, he transferred to Þór Akureyri where he played for five seasons and was selected to the Icelandic national basketball team for the first time. In 1996, he joined Keflavík where he won the national championship in 1997 and 1999 as well as the Icelandic Cup in 1997. In 1999, he moved to Germany where he played and coached, aside from the 2001–2002 season, until 2014 when he moved to his hometown of Ísafjörður to coach KFÍ (later known as Vestri). In 2022, at the age of 53, he made a comeback with Vestri in the third-tier 2. deild karla.[6]