Hubner, 21, was out of contract after Wolverhampton Wanderers released the centre-half in June. Hubner joined Wolves in 2020 from FC Den Bosch, but never made a senior appearance for the Premier League outfit.
The 15-time Indonesian international, who spent last season on loan at Japanese side Gamba Osaka, has now joined Fortuna Sittard, who announced on Tuesday that Huber had signed a three-year contract in Limburg.
"I'm happy to be back on Dutch ground," Huber said on the club website. "I had a wonderful time in England. I was able to develop both as a player and as a person. I am now taking that experience with me to Fortuna.
"I am looking forward to this new challenge in a new environment."
Hubner will replace Rodrigo Guth in Sittard. The Brazilian ace left Fortuna after three successful seasons for Argentine side Talleres.