Due to its great extent in winter and retreat in summer time, sea ice in the Southern Ocean has a great influence on the energy balance of the region and the globe. The Environmental Satellite (ENVISAT) advanced synthetic aperture radar (ASAR) data provide all time (day/night) and all weather images of the mostly cloud-covered Southern Ocean. In this study, ASAR wide swath mode (WSM) images are analyzed to determine the sea-ice characteristics of the West Antarctic region. We used ship-based sea-ice observations performed according to the ASPeCt protocol during the Oden 2007, 2008 and Nathaniel B. Palmer 2007, 2009 cruises that took place in the Bellingshausen, Amundsen and Ross Seas during spring and summer seasons. Total number of WSM images coinciding with ASPeCt observations reduced to 9 from 18 when the comparisons between the ship observations and the backscatter values are performed for ASPeCt observations falling within the ASAR acquisition time of ±2.5 hours. ASPeCt observations indicated first-year, thick first-year and multi-year ice as the main and major ice types for which the radar images yielded mean backscatter values and standard deviations as –14.5 ± 0.7, –12.9 ± 3.50 and –13.8 ± 0.3, respectively. Secondary ice types comprised mainly thin ice with fractions between 10 and 90%. Results show that backscatter values are sensitive to snow and ice properties (type and thickness) as well as the presence of a slush layer at the snow–ice interface. Relationships between the different ice types and ice-surface properties and the C-band radar backscatter are derived and examined regarding their potential to improve satellite applications such as ice-type classification or snow-depth retrieval.