A genocide memorial tombstone will be unveiled during a three-day event on Shark Island, a peninsula off the southern city of Luderitz that hosted a camp of the same name - one of several set up during German rule as part of a system of repression.
"Shark Island was not just a concentration camp, it was a death camp," said Nandiuasora Mazeingo, head of the Ovaherero Genocide Foundation, a non-profit group advocating for restorative justice for descendants of victims.
Namibia has no official day designated to commemorate what some historians have described as the 20th century's first genocide.
German settlers killed tens of thousands of men, women and children belonging to indigenous Herero and Nama people who rebelled against colonial rule in the southwest African country between 1904 and 1908.
"We have taken it upon ourselves to remember the day, at Shark Island," Mazeingo told AFP.
Several thousand people are estimated to have died at the camp, where prisoners were exposed to brutal conditions, beatings and forced labor.
Today the area hosts a state-run holiday resort, boasting 20 campsites and a lighthouse that has been refurbished for accommodation.
Descendants of the victims are disappointed that the government allows the peninsula to be "a place where people can vacation," said Mazeingo.
"It is important for us to remember where we come from and what we've been through," said Veronique Kuchekana-Chirau, who teaches the history of the genocide and its legacies to Namibian children through theatre and performing arts.
In August 1904, German soldiers chased around 80,000 Herero into what is now known as the Kalahari Desert, raping women and slaughtering their captives.
The following year, on April 22, 1905, German military commander general Lothar von Trotha, ordered the extermination of the Nama.
By 1908, at least 60,000 Herero and around 10,000 Nama were killed.
After lengthy and sometimes acrimonious negotiations, Germany in 2021 acknowledged that it had committed "genocide" in Namibia, which it colonised between 1884 and 1915.
It offered 1.1 billion euros in development aid spread over 30 years to the benefit of the Herero and Nama descendants.
But descendants of the victims and Namibian political parties are unhappy, and want to reopen talks.
"The genocide was the most grotesque and brutal act of criminality that took place in the territory that we know today as Namibia," said Mazeingo.
Namibia Marks German Genocide
WINDHOEK - Descendants of victims of genocide in Namibia will gather at the site of an infamous concentration camp this weekend to commemorate the killing of tens of thousands of people by German colonial settlers.