The breeding numbers of seabirds, including Great Cormorant, Phalacrocorax carbo, Japanese Cormorant, Phalacrocorax capillatus, Black-tailed gull, Larus crassirostris, and Slaty-backed gull, Larus schistisagus along the coastline from Cape Soya to Shari Town was censused. Confirmed were 462 nests of Great Cormorant on the nearshore bank at 4 sites, 312 nests of Japanese Cormorant at 7 sites, only one nest of Black-tailed Gull, except for the Menashidomari colony, and 1,523 nests of Slaty-backed Gull at 19 sites of which 84.5% were found on the nearshore bank. Breeding number of Slaty-backed Gulls increased between 2014 and 2019 at 4 sites. [ABSTRACT FROM AUTHOR]