SummaryObservations of 30 species of seabirds made during three passages by H. M. SubmarinesTrumpandTabardin the South-west Pacific in the southern winter months of 1961 and 1962 are presented.Wandering Albatrosses occurred northwards to 26°53'S along the coast of East Australia and to 27°12'S some 221 miles W.N.W. of Norfolk Island. Yellow-nosed Albatrosses were distributed along the coast of N.S.W. to the vicinity of Cape Byron at 28°22'S and to 30°32'S, 80 miles N.E. of Lord Howe Island. Other southern breeding species encountered well to the north along the East Australian coast included the Giant Petrel and Prion spp. It is suggested that cool, upwelling water accounts for this more northerly, coastal distribution. Some evidence was found to suggest that Wedge-tailed Shearwaters were partly migratory especially to the S.W. of Fiji. The Muttering Shearwater was noted northwards to the southern limit of the Great Barrier Reef. Facts are presented which show that the Tahiti Petrel may well disperse westwards across the Coral Sea to the vicinity of the Great Barrier Reef. Fragmentary evidence infers that the White-bellied Storm-Petrel including some of the melanistic population of Lord Howe Island, winters in the Coral Sea. Three winter-breedingPterodromapetrels were observed while other petrels of this group which have been seen by members of the R.N.B.W.S. in summer in this region, were not seen.Boobies and frigate-birds appeared scarce even in those areas adjacent to islands having large, breeding populations. Likewise, Sooty Terns were not so common as they had been expected to be. Facets of the behaviour of Australian Gannets, a Brown Booby, frigate-birds and Sooty Terns are described, the last named being noted in association with cotaceans. Sooty Terns were also seen to touch the surface of the water while fishing in calm sea conditions.Observations of the oceanography of the region are discussed. Areas of upwelling near the Australian continent were encountered although they were not strong. There was some evidence that observations of the larger numbers of vertebrates occurred in these areas of upwelling water. Records of bird flocks, fish schools and cetacean groups are discussed in the light of the work of Murphy and Ikehara (1955) and Waldron (1964) in the Central Pacific. The Coral and Tasman Seas produced most of the sightings of birds while these seemed largely absent from the New Caledonia-Fiji-New Hebrides triangle.