Joseph Banks’s relationships with two Oceanians, Tupaia and Mai, offer case studies for an examination of the role of friendship in cross-cultural scientific exchange. Tupaia, a Raiatean priest, travelled in the Endeavour through the Society Islands and to New Zealand and Australia, perishing in Batavia. Mai came to London with Tobias Furneaux in 1774 and was taken up by Banks and fêted by London society, returning to Tahiti with Cook in 1777. Scholarship has tended to emphasize the cynicism on both sides of these relationships: however the sources indicate that affective attachment and a degree of identification figured both in Banks’s depiction of the two friendships, and in the willingness of Tupaia and Mai to act as cultural informants.