Since 2011 we have been documenting seaweed diversity and abundance along a poorly studied area of the central coast of British Columbia, Canada. This first installment focuses on the Chlorophyta. To date, 42 species have been recorded, and we have obtained DNA sequences for most. Although most of these species reportedly have wide distributions along the west coast of North America, others appear to represent new northern or southern records or possible introductions, and a number have yet to be described. New southern limits are recorded for Acrosiphonia sonderi, Acrosiphonia sp., Protomonostroma undulatum, and Ulva pouliotii sp. nov., and new northern records are documented for Ulva expansa, U. stenophylla, and another undescribed species of Ulva. Among species of Cladophoraceae, we obtained a sequence only for Cladophora opaca, a Japanese species not previously recorded from North America, and an undetermined species of Rhizoclonium. We sequenced three species of Derbesia, none of which is D. marina, the currently recognized species for this area; all three require taxonomic treatment. A sequence for a shell-boring species, which is tentatively identified as Eugomontia sacculata, was also obtained. These findings extend our understanding of the diversity and biogeography of green macroalgae in the northeast Pacific.