[7] In 1955 businessman Frits den Herder together with his brother Coen, the owner of a local shipping company and playground, started collecting sea mammals.

The goal of the park according to Frits was to "make the Dutch population show respect for these most special and mythical sea mammals".

[8] In 1969 the characteristic dome was built, and in the year after opening the Dolfinarium welcomed one million visitors.

At the insistence of the mayor of Harderwijk a new foundation was set up to continue the Dolfinarium and in 1984 the shares of the company were sold to a new owner.

[10] In 2016 the Dolfinarium announced to decrease the number of dolphins at the park, citing that the population had gotten too large.

[13] The park has numerous restaurants, shops and playgrounds and a beach located on lake Wolderwijd.

In cooperation with a foundation, the Dolfinarium offers therapeutic sessions with dolphins for children with autism or Down syndrome.

[16] SOS Dolfijn is an independent foundation based in the Dolfinarium dedicated to the saving of stranded porpoises, dolphins and whales.

[18] If porpoises are deemed unfit to be released into the wild, they are sent to the Bruinvisbaai or to facilities at Ecomare on the island of Texel.

[20] In 2010 the Dolfinarium attracted worldwide attention when young orca Morgan was found exhausted and emaciated in the North Sea.

Sentiments ran high and in the end a Dutch judge decided that Morgan should be transported to Loro Parque.

[24] Dutch broadcaster Nickelodeon aired a show intended for children called Spetter!