Details of the secondary metabolite content of seven species of red algae (Rhodophyta), four species of brown algae (Phaeophyta), two species of blue-green algae (Cyanophyta), and six species of green algae (Chlorophyta) from coastal waters of North Queensland, Australia, between 15° S and 20° S of the equator, are reported. Although many of these metabolites are not new natural products, several as yet unreported compounds were identified. A specimen of the red alga Laurencia majuscula yielded the novel metabolites (1Z,8R*,9R*)-8bromochamigra-1,11(12)-dien-9-ol [31], and (1R^$,2S*,3R*,5S*,8S*,9R*)-2,3,5,9-tetramethyltricyclo[6.3.0.01,5]undecan-3-ol [32]. A sample of Dictyopteris delicatula* afforded the novel metabolite (1R*,3R*,4S*,11R*)-3,4;7,8-bisepoxydolabellan-12(18)-ene [54]. A specimen of a shallow-water Lyngbya sp. yielded the novel metabolite 8'-deacetoxymalyngamide C [60], and from a collection of Chlorodesmis fastigiata the novel metabolite (2E, 6E, 10E)-1acetoxy-3-acetoxymethyl-7, 11, 15-trimethylhexadeca-2, 6, 10, 14-tetraene [66] was isolated.