Transport Stirrup Jars (TSJs) are emblematic maritime transport containers of the Aegean Late Bronze Age, usually associated with Cretan production places and tied to Mycenaean palatial exchange systems. Despite extensive research on palatial assemblages, TSJs from non-palatial and traditionally ‘peripheral’ regions of the Greek Mainland remain underexplored. This paper presents a petrographic provenance study of TSJs recovered from the harbour site of Pefkakia in the Pagasetic Gulf (Thessaly), contributing towards filling this research gap and assessing the site’s role within wider Aegean exchange networks.

Forty-four samples, corresponding to 42 individual TSJs assigned to Late Helladic IIIA2, IIIB1 and IIIB2 contexts (ca. 14th–13th centuries BCE), were analysed using ceramic petrography. The analysis identified 20 distinct fabric groups, revealing a range of diverse sources of supply. Most vessels were found to have been produced on the island of Crete, particularly in west (Chania area) and south-central Crete (including the western Mesara), alongside fabrics attributable to broader or less specific Cretan regions. A substantial number of fabrics is associated with the Greek Mainland, including the north-eastern Peloponnese (Argolid and Corinthia) and Boeotia, with a small number of petrographic loners of uncertain provenance.

Diachronic patterns indicate a predominance of central Cretan sources in LH IIIA2, a balanced mix of west and central Cretan-origin TSJs in LH IIIB1, and a marked shift in LH IIIB2 towards west Cretan imports accompanied by a significant increase in Mainland-produced TSJs. Comparison with major palatial centres on the Mainland, the Cretan port of Kommos, and eastern Mediterranean assemblages suggests that Pefkakia received TSJs via different maritime routes, including exchange systems that might not have been fully under palatial control. The results also challenge previous assumptions about the limited circulation of Mainland-produced TSJs, and highlight the importance of non-palatial harbours in Late Bronze Age Aegean trade.