Adames was promoted to the Rays on May 22, 2018, making his major league debut the same day. He got his first hit, a solo home run off of Chris Sale, that same night. He was optioned back to Durham three days later to make room for Joey Wendle, who was returning from the paternity list. Adames was later recalled back to Tampa on June 11. On July 12, Adames was sent back down to Durham in order to receive more consistent playing time, due to the jam at middle infield between Adeiny Hechavarria, Daniel Robertson, Joey Wendle, and Matt Duffy. Adames hit .226 with a .606 OPS in his second stint. Adames was recalled a third time on July 22. On August 7, Adames hit a walk off solo home run against Miguel Castro of the Baltimore Orioles. In the month of August, Adames was awarded a spot on MLB.com's "team of the month" after slashing .318/.384/.523 with 5 home runs and 14 RBIs. Following a two-hit performance in the final game of the year, Adames ended the season with three straight multi-hit games, helping the Rays reach 90 wins for the first time since 2013. This stretch capped off a strong second half for Adames, whom hit .329 in the final two months of the season. Adames ended the season slashing .278/.348/.406 with 10 home runs in 85 games, recording a 2.0 wins above replacement.