Ratchanok Intanon, Pornpawee Chochuwong, Busanan Ongbamrungphan and Kunlavut Vitidsarn moved into the quarter-finals of the US$360,000 Korea Open Championships in Suncheon on Thursday.
They were joined by Benyapa Aimsaard and Nantakarn Aimsaard who also reached the last eight of the women's doubles event of the World Tour Super 500 event.
Fourth seed Ratchanok defeated Kirsty Gilmour of Scotland 21-14, 21-14 and next plays fellow Thai Pornpawee, who is seeded sixth, in today's quarters.
Pornpawee survived a scare against Malvika Bansod, before beating the Indian 20-22, 22-20, 21-10.
Seventh seed Busanan also had a tough match against Wang Zhiyi before beating the Chinese 21-17, 17-21, 21-18. She next faces third seed Pusarla V Sindhu who defeated Aya Ohori of Japan 21-15, 21-10. Sindhu beat the Thai in the Swiss Open final last month.
Kunlavut, who won the German Open last month, defeated Czech player Jan Louda 21-12, 21-15 and will meet Indonesian third seed Jonatan Christie in today's quarters. Christie knocked out Japan's Kodai Naraoka 21-16, 21-11.
Benyapa and Nantakarn had a comfortable win over Vivian Hoo and Lim Chiew Sien of Malaysia 21-10, 21-19. They play Korean pair Kim Min-Ji and Seong Seun-Yeon in the quarter-finals.
Kantaphon Wangcharoen was the only Thai casualty after he lost to former world No.1 Son Wan-Ho of South Korea 17-21, 14-21.
Son goes on to meet fifth seed Srikanth Kidambi of India in the last eight.
There was a huge upset in the women's single event when Chen Yufei was sent packing by Kim Ga-Eun. The Korean stunned the Chinese top seed 21-17, 21-19 to advance.
Kim will play Goh Jin Wei of Malaysia for a place in the semi-finals.
Second seed An Se-Young, however, moved safely through after the Korean downed Singapore's Yeo Jia Min 21-10, 21-10. She plays Japan's Saena Kawakami in the last eight.