This article describes early ondols (kangs) in dwellings on Neukdo Island in southeastern Korea, and in those of the Krounovka culture, Primorye, Russia, in order to test the idea that the traditions of building kang heating systems in southernmost Korea and in Primorye are related. Judging by absolute dates, Krounovka ondols are older than those in northwestern Korea. Based on a detailed analysis of ondols from 49 dwellings at the sites of Bangiri and Neukdo in southeastern Korea, four types (A–D) are described. The most common ones are L- and U-shaped ondols, constructed from stone tiles on the floor of houses (ondols of type A and B). Analysis of the clay suggests that they date to 200 BC–100 AD. In the areas of the Krounovka (Tuanjie) culture in Primorye, Northeastern Korea and Manchuria, ondols of similar construction have been known as early as the 3rd century BC. Comparative analysis of heating systems and dates of early ondols in dwellings of southeastern Korea and Primorye confirm the hypothesis of the appearance in the 2nd century BC of dwellings with early ondols in the southernmost part of Korea under the influence of the traditions of the Krounovka culture of Primorye. This process was evidently triggered by the migration of the Krounovka people along the Pacific coast first to northeast Korea, and then to the southernmost part of the Korean peninsula.