Study on the Autonomous Reef Monitoring Structures (ARMS) in Sweden in the framework of ARMS-MBON programme. Samples were sequenced for the i) COI gene using mlCOIintF and jgHCO2198 primers, ii) ITS using ITS1f and ITS2 primers, and iii) 18S rRNA gene using All18SF and All18SR primers. Details can be found in http://arms-mbon.eu/ The European ARMS programme (ARMS-MBON) is a network of Autonomous Reef Monitoring Structures (ARMS) placed in the vicinity of marine stations, ports, marinas, and Long-Term Ecological Research (LTER) sites distributed over Europe and polar regions. The project was primarily funded through the Joint Research Activity (JRA1) of ASSEMBLE Plus, with financial contributions from the Swedish Agency for Marine and Water Management, the Interreg project GEANS and with considerable in-kind contributions by the participating institutes. The project is an activity of the Genomic observatories network with relations to the European Marine Biological Resource Center (EMBRC). ASSEMBLE Plus as a project finished in 2022, but the ARMS-MBON programme continues under EMO BON.