Associations between the nestling and facultatively boring pectinid Pedum spondyloideum and scleractinian host corals are reported for the 1st time from the west coast of Thailand, Andaman Sea, eastern Indian Ocean. Pedum individuals used 14 hosts, including the previously unrecorded species of Cyphastrea serailia, Favites abdita, Galaxea astreata, Montipora caliculata, and Pachyseris rugosa. In addition, this is the 1st time that associations between Pedum and the calcareous hydrozoans, Millepora dichotoma and Mil. exaesa, were observed.