It is 62 mm long. Both sexes have azure blue spots on each abdominal segment and the thorax also has azure markings. The markings on the male are brighter and more conspicuous than in the female. The female also has a brown colour form.
This species flies in sunshine, and will also bask on stones or tree trunks. It shelters in heather or similar low vegetation in dull weather. Unique to this species is that the blue of the male pales to a more grey colour at lower temperatures.
- Clausnitzer, V. (2007). "Aeshna caerulea". IUCN Red List of Threatened Species. Version 2010.3. International Union for Conservation of Nature. Retrieved 29 September 2011.
- "Azure Hawker". British Dragonfly Society. Retrieved 29 September 2011.
- Willet, Jonathan (April 2013). "The Azure Hawker Aeshna caerulea (Ström)". Journal of the British Dragonfly Society 29: 5.