Males become sexually mature at around 4–6 years of age, and females at around 6–9 years of age.
Finless Porpoises are reported to eat fish and shrimp in the Yangtze River, and fish, shrimp and squid in the Yellow Sea/Bohai area and off Pakistan. In Japanese waters they are known to eat fish, shrimp, squid, cuttle fish and octopuses. Finless Porpoises are opportunistic feeders utilising various kinds of available food items available in their habitat. Seasonal changes in their diets have not been studied. They also apparently ingest some plant material when living in estuaries, mangroves, and rivers including leaves, rice, and eggs deposited on vegetation.