Intanon participated in the Malaysia Masters Super 500, hoping to defend her title.
She won all of her matches in straight sets,  to set up a final against Carolina Marín.
She beat Marin 21–9, 22–20 to successfully defend her title.
At the final of German Open Super 300 She lost to Akane Yamaguchi in three games, losing 23–25 in the deciding game.
Intanon then won her third Indian Open title by beating He Bingjiao with 21–15, 21–14.
This was Intanon's first victory over her.
She lost the final of Thailand Open to her nemesis Chen Yufei in close 2 games.
She won the bronze medal at 2019 Basel World Championship after losing to Nozomi Okuhara in three tight games 21–17, 18–21, 21–15 in the semifinals.
Intanon was just one points away from Korea Open Title when playing against He Bingjiao in final, but was denied by tenacity of her opponent who saved 4 match points and won the next game to snatch out victory from Intanon.

Intanon failed an out-of-competition drug test in April but the Thai star was not banned by the BWF.
The BWF statement reads: "The ethics hearing panel determined Ms. Ratchanok Intanon committed an anti-doping rule violation, but as the athlete was able to demonstrate that her adverse analytical finding was related to the ingestion of meat contaminated with clenbuterol, she was found to bear no fault or negligence for the violation, and thus no period of ineligibility has been imposed on her."
Her jinx of losing against Chen Yufei continued when she lost to her in the final of Hongkong Open.
She participated in World Tour Finals, where she beat Busanan Ongbamrungphan in straight games in Round 1, she lost to Tai tzu-ying in very hardly contested match, failing in 3 sets.
Her hopes of qualifying for knockout round disappear when she lost to Nozomi Okuhara in the last group match.
Intanon participated in the Malaysia Masters Super 500, hoping to defend her title. She won all of her matches in straight sets,  to set up a final against Carolina Marín. She beat Marin 21–9, 22–20 to successfully defend her title. At the final of German Open Super 300 She lost to Akane Yamaguchi in three games, losing 23–25 in the deciding game. Intanon then won her third Indian Open title by beating He Bingjiao with 21–15, 21–14. This was Intanon's first victory over her. She lost the final of Thailand Open to her nemesis Chen Yufei in close 2 games. She won the bronze medal at 2019 Basel World Championship after losing to Nozomi Okuhara in three tight games 21–17, 18–21, 21–15 in the semifinals. Intanon was just one points away from Korea Open Title when playing against He Bingjiao in final, but was denied by tenacity of her opponent who saved 4 match points and won the next game to snatch out victory from Intanon. 
Intanon failed an out-of-competition drug test in April but the Thai star was not banned by the BWF. The BWF statement reads: "The ethics hearing panel determined Ms. Ratchanok Intanon committed an anti-doping rule violation, but as the athlete was able to demonstrate that her adverse analytical finding was related to the ingestion of meat contaminated with clenbuterol, she was found to bear no fault or negligence for the violation, and thus no period of ineligibility has been imposed on her." Her jinx of losing against Chen Yufei continued when she lost to her in the final of Hongkong Open. She participated in World Tour Finals, where she beat Busanan Ongbamrungphan in straight games in Round 1, she lost to Tai tzu-ying in very hardly contested match, failing in 3 sets. Her hopes of qualifying for knockout round disappear when she lost to Nozomi Okuhara in the last group match.
Ratchanok Intanon