Students face several challenges when asked to locate relevant and credible information from the internet. This article introduces three principles for designing online inquiry lessons and documents what we learned from five language arts teachers from Finland who implemented and provided feedback on a learning unit framed in those design principles. Teachers implemented a researcher-designed online inquiry unit in nine upper secondary school classrooms. The unit included four 75-minute lessons sequenced to support the location, evaluation, and synthesis of information students encountered in an online inquiry task. Teachers’ diaries revealed their impressions of the unit, problems encountered, and exceptions made to the designed plan. Follow-up interviews revealed additional insights about appropriate time allocation, clear instruction, and areas where students benefit from explicit guidance in strategy use. Findings suggest a researcher-teacher collaboration can be a fruitful endeavor to assist in advancing the design of productive online inquiry activities.