On 1 August 2002, the Castle Museum was opened to celebrate the 750^th anniversary of the Klaipėda City. On that day, the idea that city leaders, archaeologists and historians had been fostering for several decades, to make the oldest part of the city—the site of the Klaipėda Castle—accessible to everyone, became a reality.

The exposition in Prince Friedrich’s postern, located under the earth rampart (bastion), was dedicated to introduce visitors to the development of the Klaipėda Castle and the city in the 13t^h – 17^th centuries.  It is known that artillery was stored in this authentic vault in the 17^th century. NOTE: This exposition is currently not available at the museum.

On 1 August 2006, the continuation of the Castle Museum’s exposition was opened in the restored postern and casemates of the Prince Karl’s bastion. The main entrance takes visitors to the 18^th century Klaipėda, and then onwards to the 19^th and 20^th centuries history of the city. More than 30 stands display views of the city, maps, plans, and portraits of the city’s most famous citizens – burgomasters and merchants. Documents, engravings and photographs illustrate the historical events of 1807–1809, 1920–1923, 1939 and 1945. The exposition reflects the economy, culture and everyday life of the citizens throughout the centuries. All used historical material comes from the collections of the History Museum of the Lithuania Minor, Lithuanian and German archives and private collections.

The authentic postern niches present archaeological finds from the 18^th century: blacksmiths’ and potters’ wares, imported products from Klaipėda, stamps from the second half of the 19^th century, a ceremonial goblet of the Masonic lodge made by local craftsmen in 1850, household items and weapons from the 20^th century. The mannequins depicting a city family with reconstructed early 20^th century clothes, as well as a model of the three-masted barque Achilles, built in 1864 by the most famous shipbuilder of Klaipėda, Behrend Pieper, also attract a lot of attention of the museum visitors. The story of Klaipėda in the second half of the 20^th century ends with the most characteristic exhibits illustrating the Soviet era and the most recent period of the city’s history.

In 2012, another computer terminal was installed in the Castle Museum. This is the result of the project “Klaipėda History Coming to Life. The Site of the Klaipėda Castle”. The material here provides a detailed and illustrative presentation of the development of Klaipėda Castle. Information is presented in Lithuanian, English, Russian and German.

When visiting the site of the Klaipėda Castle, it is also worth seeing the foundations of the 14^th – 17^th centuries buildings uncovered by archaeologists, together with the impressive remains of the Grand Gunpowder Tower. In addition, while exploring the ruins outside, visitors can also walk along the 16^th century pavement, the oldest in Klaipėda, as well as climb on Friedrich‘s bastion to admire the panorama of the city.