From the Pacific to the Indian Ocean the passage was accomplished in nineteen days.

"Perhaps," commented Flinders, "no space of 3 1/2 degrees in length presents more dangers than Torres Strait, but with caution and perseverance the captains, Bligh and Portlock, proved them to be surmountable, and within a reasonable time." Bligh's Entrance and Portlock Reef, marked on modern charts, are reminders of a feat of navigation which even nowadays, with the dangers accurately described, and the well-equipped Torres Strait pilot service to aid them, mariners recognise as pregnant with serious risks.

On this occasion it was also attended with incidents which make it worth while to utilise Flinders' notes, since they are of some biographical importance.
The high lands of the south-eastern extremity of Papua (New Guinea), were passed on August 30th, and at dusk on the following day breakers "thundering on the reef" were sighted ahead.

On September 1st the vessels edged round the north end of Portlock Reef.

Thence the monotonous record of soundings, shoals, reefs seen and charted, passages tried and abandoned, in the prolonged attempt to negotiate a clear course through the baffling coral barrier, is relieved by the story of one or two sharp brushes with armed Papuans in their long, deftly-handled canoes.