Acoustic environments provide a wealth of information for marine organisms, allowing them to navigate and communicate in their underwater habitats. The increasing pressures of anthropogenic stressors on marine environments are also progressively affecting the acoustic underwater realms across our world’s oceans. The sea ice-covered areas of polar oceans are considered to harbor some of the last still relatively pristine underwater soundscapes, offering the unique opportunity to boost our understanding of intact marine underwater soundscapes. Soundscape data are being collected across large temporal and geographical scales, now rendering it possible to analyze soundscape data over years to decades and spanning ocean basins. The rise of various ecoacoustic metrics as a tool to describe soundscape properties offers a scalable approach to effectively summarize the acoustic status of polar ocean ecosystems. In this chapter, the authors describe typical polar ocean soundscape components, outline posing threats and alterations to polar acoustic environments, and establish a framework that includes ecoacoustic metrics for capturing and characterizing polar marine soundscapes across large spatiotemporal scales.