Two billion people globally are using faecal-contaminated water. Consumption of Escherichia coli in fecal-contaminated waters poses a health risk due to its potential to cause diseases which highlights the need for understanding its factors for contamination and its antimicrobial resistance profile. Membrane filtration method was used to culture and isolate E. coli. The disk diffusion method was used to identify resistance of E. coli isolated and sanitary inspection was used to identify the contamination risk. The study found 44.8% of groundwater samples (n=73) were contaminated with E. coli, with 83.6% (n=61) of isolates showing antibiotic resistance. A Chi-square test revealed a statistically significant difference in resistance proportions across tested antibiotics (p < 0.001). High resistance rates were noted for cefazolin (56.16%, n=41), nitrofurantoin (54.79%, n=40), amoxicillin-clavulanic acid (45.21%, n=33), and ceftriaxone (42.47%, n=31). Additionally, 70% of E. coli isolates (n=51) were multidrug-resistant. Sanitary inspections showed 46.2% (n=18) of dug wells had a high sanitary risk, while 73.3% (n=44) of boreholes had a low contamination-risk. However, even boreholes with a low sanitary risk showed a high rate of E. coli contamination. Tube wells with hand pumps and dug wells at high sanitary risk also had elevated rates of E. coli contamination. Findings showed high prevalence of antibiotic-resistant E. coli in groundwater in Bagamoyo, and highlight need for advocacy of proper use of antibiotics and proper hygiene to prevent the spread of resistant E. coli in groundwater. published by the Journal of Biodiversity and Environmental Sciences | JBES