The Society has been involved in many major excavations, some of which have improved understanding of prehistory and history not just in Cornwall itself, but also in the wider world, most notably the work at Carn Brea which threw so much light on the Early Neolithic period. Most of the larger excavations took place before the creation in 1975 of the Cornwall Committee for Rescue Archaeology (later the Cornwall Archaeological Unit) and then the development of planning-based procedures that saw most rescue excavations in the hands of professional units.
Since then, the CAS has largely played an important supporting role on rescue and research projects. The 2025 Castilly Henge project will be another example of this.
- Castilly Henge (1962)
- The Rumps cliff castle (1963)
- St Dennis. Possible hillfort (1962)
- Old Lanyon later medieval farmstead (1964)
- Crane Godrevy, Gwithian, round and later medieval settlement
- Carvossa, Roman period defended settlement
- Carn Brea, Neolithic tor enclosure and Iron Age hillfort
- Lesquite Quoit
- Trebartha Cist
- Innis Downs ring cairn
CAS has also contributed volunteers and other support to numerous other investigations
- Castle-an-Dinas hillfort (1962)
- Launceston castle
- Halangy Down prehistoric settlement
- Nanstallon Roman fort (1965)
- Treworld medieval longhouse hamlet (1963)
- Longstone Downs menhir
- Trethurgy Round
- The St Austell barrows (Watch Hill, Caerloggas, Trenance and Cocksbarrow)
- Carlidnack Round
- Field walking, watching briefs and trial trenches along the Bodmin Bypass