Citizen science projects utilize non-professionals to collect data for scientific research and monitoring projects. Citizen scientists can collect data at temporal and spatial scales that may be unobtainable by individual scientists or research teams. On the island of Newfoundland, Canada, capelin (Mallotus villosus) spawn at both beach and coastal deep-water (sub-tidal, < 40 m) habitats. Timing of spawning is a predictor of capelin year-class strength. From 1991-2021, a network of citizen scientists, recruited and paid by Science Branch, Fisheries and Oceans Canada, monitored the timing, duration, and intensity of capelin beach spawning from June until August each year on the southeast and east coasts of the island (Northwest Atlantic Fisheries Organization [NAFO] Divisions [Divs.] 3KLPs). Over the three decades of the spawning diary program, a total of 56 beaches were monitored with most of the surveyed beaches being located in Div. 3L (33 beaches) followed by Div. 3K (17 beaches) and Div. 3Ps (6 beaches). Five years was the median length of time each participant collected spawning data (range: 1-29 years). The spatial extent of spawning diary coverage was similar among years with on average a similar number of beaches monitored in Div. 3K (n = 7) and Div. 3L (n = 9) and two beaches monitored in Div. 3Ps each year. Median first day of beach spawning was July 4 in Divs. 3KLPs, and there was decadal stability in median first day of beach spawning (July 3-5 in each decade). Median spawning duration was 11 days. A comparison to similarly detailed beach spawning data collected from questionnaires by Dr. Wilfred Templeman in 1941-1942 indicates capelin are currently (1991-2021) spawning on average 16 days later and for 14 days shorter. The continued collection of beach spawning data across the island of Newfoundland will aid in the provision of science advice for the management of this linchpin forage fish species.