Fermentation of milk enhances its nutritional and biological activity through the improvement of the bioavailability of nutrients and the production of bioactive compounds. Coconut milk was fermented withLactiplantibacillus plantarumngue16. The aim of this study was to evaluate the effect of fermentation and cold storage for 28 days on physicochemical characteristics, shelf life, and antioxidant and antibacterial activities of coconut milk as well as its proximate and chemical compositions. The pH of fermented milk decreased from 4.26 to 3.92 on the 28thday during cold storage. The viable cell count of lactic acid bacteria (LAB) in fermented coconut milk was significantly increased during fermentation and cold storage period (1 to 14 days), reaching 6.4 × 108CFU/mL, and then decreased significantly after 14 days to 1.6 × 108CFU/mL at 28 days. Yeast and molds in fermented coconut milk were only detected on the 21stand 28thdays of cold storage, which ranged from 1.7 × 102to 1.2 × 104CFU/mL, respectively. However, the growth of coliforms andE. coliwas observed on the 14thuntil the 28thday of cold storage. The fermented coconut milk demonstrated strong antibacterial activity againstStaphylococcus aureus,Bacillus subtilis,Escherichia coli,Cronobacter sakazakii,Bacillus cereus, andSalmonella typhimuriumcompared to fresh coconut milk. Fermented coconut milk had the greatest 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) values, with 67.1% and 61.961 mmol/g at day 14 of cold storage, respectively. Forty metabolites were detected in fermented and pasteurized coconut milk by proton nuclear magnetic resonance (1H NMR) metabolomics. The principal component analysis (PCA) showed clear difference between the fermented and pasteurized coconut milk as well as the studied cold storage days. The metabolites responsible for this variation were ethanol, valine, GABA, arginine, lactic acid, acetoin, alanine, phenylalanine, acetic acid, methionine, acetone, pyruvate, succinic acid, malic acid, tryptophan, uridine, uracil, and cytosin, which were higher in fermented coconut milk. However, sugars and other identified compounds were higher in fresh coconut milk. The findings of this study show that fermentation of coconut milk withL. plantarumngue16 had high potential benefits to extending its shelf life and improved biological activities as well as other beneficial nutrients.