Summary Larvae of the spionid polychaete, Polydora ligni Webster 1879, were forced to delay settlement and metamorphosis for 6 days by withholding suitable substrata. Daily mortality was 2.5% during the competent period of larval development. Starvation increased mortality to 5.4% per day. A high percentage of the control (nondelayed) and fed, delayed larvae metamorphosed (70–81%) and the newly metamorphosed juveniles were the same size in these 2 groups. However, delay combined with starvation greatly reduced metamorphic success (to 15%) and juvenile size. Delay (with feeding) significantly decreased somatic and reproductive growth of post-metamorphic juveniles compared to the nondelayed control group. Costs of delayed settlement and metamorphosis could partially offset the advantages of extending the larval period for benthic habitat selection.