Suzanne Frey-Kupper works on Greek, Punic and Roman coinage, and the Western Mediterranean. She is interested in coins from archaeological contexts and as part of ancient material culture testifying to historical processes, technical and artistic skills, social and economic phenomena, and religious beliefs. With Keith Rutter and John Morcom she prepares the volume Sicily and the Adjacent Islands of Historia Numorum which is the standard reference catalogue of Ancient Greek coins. She has published the coin finds from many major archaeological sites, such as Rome, Lilybaion, Iaitas, Entella, Malta (sanctuary of Tas-Silġ), Cossyra and Carthage , and has been entrusted with the study of further coin series (Rome, the late Roman destruction layer of the Basilica Aemilia on the Forum Romanum; Selinunte, acropolis with the area of temples B and C; Gozo, Għar ix-xiħ ; Carthage, Bir Messaouda and Rue Ibn Chabâat; Aventicum in Switzerland, sanctuaries).
Milestones in her activities were the creation of a number of enduring projects: the Swiss Working Group on Coin Finds (SAF/GSETM), founded in 1985 under her chairmanship, which in turn led to the creation of the Inventory of Swiss Coin Finds (IFS/ITMS of the Swiss Academy of Humanities and Social Sciences). From 1991, for eight years, she directed the IFS/ITMS in Lausanne, and launched the series with the same title. In 1995, she established the series Untersuchungen zu Numismatik und Geldgeschichte / Études de numismatique et d’histoire monétaire.
Suzanne Frey-Kupper was also a scientific collaborator of several Swiss institutions in order to ensure the study and publication of their coin finds, especially of Aventicum, the Roman capital of the Helvetii, and of Solothurn and Bern. She concurrently worked on various excavation projects in the Western Mediterranean and from 2008 was a Lecturer in numismatics at the University of Zurich, Department of Ancient History.