After a brief hiatus, Tanahashi returned during the New Japan Cup, reaching the finals only to be defeated by Zack Sabre Jr. At Sakura Genesis 2018, Tanahashi teamed with fellow Taguchi Japan members Juice Robinson and David Finlay to defeat Chaos members Hirooki Goto, Jay White and Yoshi-Hashi. Later in the night, Tanahashi would confront IWGP Heavyweight Champion Kazuchika Okada after Okada defeated Sabre to tie Tanahashi's record for most successful title defenses with eleven, indicating a potential title match in the near future. Their match took place on night two of Wrestling Dontaku 2018, where Tanahashi was unsuccessful in winning the championship, and in the process having his record of most successful title defences in one reign broken, as Okada defended the championship successfully for the twelfth time. Tanahashi then took part in the 2018 G1 Climax, where he finished with a record of seven wins, one draw, and one loss, thus setting a new record for the most points in the current 20-man G1 format with 15 and advancing to the finals, where he defeated Kota Ibushi to win his third G1 Climax tournament. This earned him the right to challenge for the IWGP Heavyweight Championship at Wrestle Kingdom 13 that he would have to defend for the remainder of the year and marked the tenth time he would main event the show. As the only men he failed to defeat in his block, Tanahashi nominated Okada and White to be his challengers for the contract. On September 23, at Destruction in Kobe, Tanahashi defeated Okada to retain the contract and was promptly assaulted by White. On October 8, at King of Pro-Wrestling, he retained the contract against White.