Izu islands to Tokyo is pretty good - the 3 albatross species including lots of short-tailed, 1000s of streaked shearwater and a sadly unidentifiable dark-rumped storm-petrel when I did it. Not too expensive either if you don't mind roughing it a bit on the overnight outward leg.What are the best scheduled ferry services worldwide for pelagic birding? The only one I've taken that was especially notable was the now defunct Kushiro - Tokyo service, which was truly epic (3 species of albatross including 2,500 Laysan, 8 species of alcid, Fork-tailed Storm Petrel etc, plus many sea ducks, divers, Steller's Sea Eagle etc inshore. All for £80.
The ferry to the Ogasawara islands must be up there too, although not cheap. Alaska Marine Highway to Dutch Harbor?