Societal crises, such as the COVID-19 pandemic, produce societal instability and create a fertile ground for radicalization. Extremists exploit such crises by distributing disinformation to amplify uncertainty and distrust among the public. Based on these developments, this study presents a longitudinal analysis of far-right communication on fringe platforms, demonstrating radicalization dynamics. Public Telegram communication of three movements active in Germany (QAnon, Identitarian Movement, Querdenken) was analyzed through a quantitative content analysis of 4500 messages posted to nine channels between March 2020 and February 2021. We study the movements' discourse using several indicators of radicalization dynamics. The increasing prevalence of conspiracy narratives, anti-elitism, political activism, and support for violence indicate radicalization dynamics in these movements’ online communication. However, these dynamics varied within the movements. It can be concluded that, when studying radicalization dynamics online, it is crucial to not just focus on one single indicator, but consider longitudinal changes across several indicators, ideally comparing different movements.