Introduction: Few studies have addressed teacher trainees' information acquisition in the context of a task. The paper reports findings from an empirical study on teacher trainees' use of information (seeking) channels and sources, and their modes of information acquisition in lesson planning. Method: Semi-structured (retrospectively held) individual interviews and supporting classroom observations were conducted. Analysis: Inductive thematic analysis was applied to the transcribed interviews. Findings: The trainees used various information channels for a single lesson plan, mainly their personal collections and the Web. The information sources acquired comprised documentary and interpersonal sources, various media and contents. Their information acquisition encompasses a continuum of modes beginning with purposeful and goal-orientated, and ending up with accidental and passive modes of information acquisition. Conclusions: Trainees' information acquisition for lesson plans cannot be described only in terms of their present activities or goal-orientated information seeking behaviour. The use of personal collections of information sources, gathered in the past in anticipation of future lessons, constitutes an essential characteristic of their information acquisition. Trainees' modes of information acquisition reflect continuity across work tasks, which calls for capturing across task perspectives in information seeking models. (Contains 2 tables.)