The COVID-19 pandemic has led to unprecedented life disruptions among young adults, including increased job insecurity and financial strain. Mental health problems and substance use have also increased during the pandemic, with young adults particularly vulnerable to experiencing these challenges. This study examines trajectories of financial distress among young adults during the pandemic and their associations with depression, anxiety, and hazardous alcohol and cannabis use. Data from 473 young adults (ages 22-29) recruited in the Northwest United States were collected from April/May 2020 to July/August 2021. Financial distress trajectories were identified using growth mixture modeling. Negative binomial models were used to examine associations between financial distress trajectories and distal outcomes of depression, anxiety, alcohol, and cannabis use. Three distinct trajectories were identified, revealing Low, Moderate, and High financial distress experiences. Individuals with "Moderate" and "High" trajectories showed significantly greater depressive and anxiety symptom scores compared with those in the "Low" financial distress trajectory group. Trajectories were not associated with subsequent levels of alcohol or cannabis use. Young adult mental health remains a priority during periods of economic downturn. Providers must be aware of the psychological challenges imposed by financial distress among young adults to address worsening mental health symptoms.