he made his professional regular season debut and first career start in the cincinnati bengals' at the indianapolis colts and recorded eight solo tackles in their 34–23 victory. on september 13, 2018, bates recorded three solo tackles, broke up a pass, and made his first-career interception during a 34–23 victory against the baltimore ravens in week 2. bates made his first career interception off a pass attempt by joe flacco, that was originally intended for wide receiver michael crabtree, and returned it for a 21-yard gain in the first quarter. in week 7, he collected a season-high 12 combined tackles (seven solo) during the bengals’ 45-10 loss at the kansas city chiefs. on october 28, 2018, bates recorded six solo tackles, two pass deflections, and returned an interception by for his first career touchdown during a 37-34 victory against the tampa bay buccaneers in week 8. bates intercepted a pass by buccaneers’ quarterback jameis winston, that was intended for wide receiver adam humphries, and returned it for a 21-yard touchdown. on december 31, 2018, the cincinnati bengals announced their decision to fire head coach marvin lewis after the bengals finished with a 6-10 record. he started all 16 games as a rookie in 2018 and recorded a team-leading 111 combined tackles (73 solo), seven pass deflections, three interceptions, and one touchdown. he received an overall grade of 79.9 from pro football focus, which ranked as the 11th best grade among safeties in 2018.