Taiwan and Nauru are expected to sign a maritime agreement as part of a state visit by President Tsai Ing-Wen.
Ms Tsai is in Nauru in the second leg of her eight-day trip to four Pacific nations where she is shoring up support.
Taiwan's Central News Agency reports she will hold talks with her Nauru counterpart, Baron Waqa, and the two will sign a sea patrol cooperation accord.
Ms Tsai will leave tomorrow for the Marshall Islands.