Sports events involving significant public spending are expected to create a multiplier impact on the local economy. This study investigates the economic impacts of the F1 Powerboat Championship held at Lake Toba, Indonesia, focusing on government spending on event preparation and implementation as well as expenditure by participants and visitors. Employing an input-output model to estimate the multiplier impact and primary data collected from 70 domestic and international respondents, this study estimated a total economic stimulus of IDR 329.68 billion in Toba District, leading to an additional output of IDR 510.37 billion. This produced an economic value-added of IDR 254.88 billion, contributing to 2.64% to the Gross Regional Domestic Product (GRDP) of Toba District in 2023, with IDR 72.95 billion benefiting worker households. The event also created 6,496 employment opportunities in Toba District, albeit predominantly temporary. Most international and domestic visitors expressed an intention to revisit Lake Toba and Toba District outside the event, with international attendees likely to recommend Lake Toba to their relatives and families. Strengthening the interlinkages in the local economy and improving service quality can further amplify the economic impacts of the event. The study concludes with academic and practical implications of the findings. © 2026 Informa UK Limited, trading as Taylor & Francis Group.