Chittick's expeditions and residence on the Swahili Coast produced a body of research into the pre-colonial sites Kilwa Kisiwani and the port of Manda Island.
From late October to early December 1975, at the invitation of the Somali government, Chittick led a British-Somali archaeological expedition in the northern half of Somalia.
Members of the party included the Director of the Somali National Museum in Mogadishu, Sa'id Ahmad Warsame, as well as 'Ali 'Abd al-Rahman and Fabby Nielson.
Financed by the Somali authorities, the reconnaissance mission found numerous examples of historical artefacts and structures, including ancient coins, Roman pottery, drystone buildings, cairns, mosques, walled enclosures, standing stones and platform monuments.
Based on his discoveries, Chittick suggested in particular that the Damo site in the Hafun peninsula likely corresponded with the Periplus' "Market and Cape of Spices".