Abstract Palaeozoic sediments of Austria are separated by the Periadriatic Fault into Eastern Alpine (Upper, Middle and Lower Austroalpine) and Southern Alpine units. We herein present six case studies showing up the different development of shallow-marine communities with special regard to carbonate factories and shell pavements occurring in both regions during the Siluro-Devonian time span. Upper Silurian-Upper Devonian deposits of the Eastern Alps comprise accumulations of serpulid tubes (Southern Burgenland) and Septatrypa pavements, Amphipora mounds, coral-stromatoporoid–biostromes and Stachyodes–auloporoid beds regarded as pioneer reef communities (Graz Palaeozoic), respectively. Lower Silurian strata of the Southern Alps consist of pelagic sediments persisting to the Upper Silurian and therefore differ from contemporaneous successions in the Eastern Alps. Intercalated in Ludlow orthocerid limestone beds Cardiola pavements appear (Carnic Alps). Within the Lower Devonian sequence, mounds were built by baffling calcareous algae and tabulozoan communities. Coral–stromatoporoid patch reefs occur during the Pragian, Givetian and Frasnian stages.