A total of 61 specimens representing five species of shag – Auckland Island shag Leucocarbo colensoi, little pied shag Microcarbo melanoleucos brevirostris, black shag Phalacrocorax carbo novaehollandiae, Otago shag Leucocarbo chalconotus and spotted shag Phalacrocorax punctatus – from the coast around Otago, South Island, New Zealand, were examined for helminths. A total of 18 helminth species was found: six nematodes (Anisakis pegreffi, Contracaecum rudolphii E, Baruscapillaria sp., Cosmocephalus jaenschi, Ingliseria cirrohamata, Desmidocercella australis), four trematodes (Apatemon sp. ‘jamiesoni’, Cardiocephaloides ovicorpus, Apophallus sp., Microphallidae gen. sp.), four cestodes (Microsomacanthus cormoranti, Microsomacanthus sp., Paradilepis urceina, Tetrabothrius sp.) and four acanthocephalans (Andracantha leucocarboi, A. sigma, Corynosoma hannae, Profilicollis novaezelandensis). Descriptions are provided for females of C. jaenschi and D. australis, which were previously undescribed. The data include 20 new host records and seven new locality records. New 18S ribosomal DNA and internal transcribed spacer (ITS1 and ITS2) DNA sequences have been provided where specimen conditions permitted. These data add considerably to our sparse knowledge of helminths in New Zealand shags, and provide a baseline for observations of change in the future.