Indonesian culture is inseparable from mathematics. Mathematics and culture are something that cannot be avoided in everyday life, because culture is a whole and comprehensive unity, prevailing in a society while mathematics is the knowledge used by humans in solving everyday problems. In the context of boat culture, people unconsciously apply ethnomathematics in everyday life, where it becomes the source or basis of mathematics in various fields, including boats found in Makassar society, namely Lepa-lepa boats and Lambo boats. Lepa-lepa boat is a traditional canoe originating from the eastern region of the Indonesian archipelago, mainly used in Makassar waters. This boat is generally used as a means of transportation for fishermen over short distances, but can also be used for inter-island voyages. Lambo boat is a means of transportation used by some Selayar people who have the character of an accomplished nomad and sailor. The purpose of this study is to find out the concept of geometry contained in the traditional boat components of the Makassar community. The method used in this study is qualitative research with an ethnographic approach. Data collection techniques were carried out using observation, interview, and documentation methods. The results showed that there are ethnomathematical concepts of geometry contained in Lambo boats and Lepa-lepa boats. Therefore, the potential of geometry in mathematics learning found in traditional Makassar boats is the concept of triangle and trapezoidal geometry found on the lambo boat sail and oval flat build found on the lepa-lepa boat oars.