At the international community, Traditional Ecological Knowledge (TEKs) have been recognized and acknowledged the important roles of indigenous peoples to tackle climate change. The cultural practice, cultural belief and adaptive capacity in managing nature by the Orang Suku Laut (OSL), Indonesian indigenous group who are living as nomads in the sea, would be considered as the key drivers to achieve the effectiveness of climate change adaptation (CCA). This research aimed to study the TEKs of indigenous peoples on CCA of the OSL, Lingga Regency, Riau Islands Province, Indonesia, for appropriate CCA policy implemented at their communities. Data collection was obtained from the desk study as a secondary data, a field observation, and an in-depth interview for a primary data by using a set of semi-structured questionnaires. The number of respondents (n=77) were selected by using the purposive-sampling method which consists of the native's OSL (37.66 percent) and related stakeholders (62.34 percent) who are working with the OSL including government officials, society, expert and academic, non-governmental organization, and private sector. The OSL interviewed was divided into four groups, namely headmen (31.03 percent), elder (27.59 percent), youth (24.14 percent), and women (17.24 percent). They are living in the land and staying in the boat. Data collected were analyzed using the statistical and descriptive and content analysis. The study found that all of the respondents well comprehended about climate change and its impacts. 97.12 percent of the respondents knew the meaning of climate change, and 98.28 percent realized that the current climate is changing. Therefore, the TEKs of the OSL�was found as adequate activities in combating climate change through the interconnection among their cultural practice (53.3 percent), cultural belief (33.3 percent), and adaptive capacity (13.4 percent). The TEKs on cultural practices are weather forecasting, traditional fishing method, traditional medicine, disaster preparedness, cultural astronomy, aquaculture, mangrove conservation, and coral reef conservation. Meanwhile, for the cultural belief of the OSL included customary law (Pantang Larang), mantra and spell (Pengasih and Ilmu), blessing ceremony (Zemah Kampung), washing ceremony (Melange Ceremony), and multiple purposes materials (Kajang). For adaptive capacities, vernacular architecture and local migration are their TEKs. The study also found that their TEKs on CCA has degraded by generations. Regarding policy and development project on CCA related to the OSL, it disclosed that there is no CCA' project for them presently both from governmental officials and related stakeholders. Nevertheless, they plan to take consideration for the TEKs regarding the autonomous adaptation of the Orang Suku Laut as well as guided by the Indonesian action plans on CCA (RAN-API). The study would highly recommend the involvement of the OSL through the Free, Prior, and Informed Consent (FPIC) participation in protecting the TEKs on CCA as friendly environmental practice.