Extending from existing research on how public libraries offer information literacy (IL) instruction through classes or programs, the purpose of this research was to explore how public librarians provide IL instruction through individual interactions with patrons. US public librarians recorded their impressions of instructional interactions over a five-day period using an online diary instrument. Key findings were that public librarians incorporate a range of IL concepts in their interactions with patrons, across a wide variety of expressed information needs, with most of the instruction directed toward helping patrons plan their information tasks, access information, and judge information. Secondary themes showed that although librarians believed strongly in the value and importance of providing instruction, individual and situational factors presented barriers to effective instruction. This research contributes to an understanding of how IL instruction in public library settings differs from school and academic library settings and raises some questions around the need for instructional resources focused more specifically around the needs of the public library to facilitate effective instruction.