In addition to HSC Haltern-Sythen, 18 other teams from 7 different countries played in Boys 21. They were divided into 2 different groups, whereof HSC Haltern-Sythen could be found in Group 2 together with Lugi HF 1, HV Dynamico, Täby HBK, IK Baltichov, Schiffdorf TV, Sokol Velke Mezirici and Kärra HF. HSC Haltern-Sythen continued to B-Play-off after reaching 8:th place in Group 2. In the playoff they made it to 1/8 Final, but lost it against HBC Evergem with 0-10. In the Final, HK Ankaret won over Täby HBK and became the winner of B-Play-off in Boys 21. HSC Haltern-Sythen also participated in Boys 21 during Partille Cup 2023. They reached the 1/4 Final in B21 B-Play-off, but lost it against HK Ankaret with 13-23.