Schnyner, a six-time winner on the WTA Tour, moved into her third semifinal of the year. She also reached the Gold Coast semifinals during the opening week of 2001 and the Vienna final in July.
Kremer, who was making her third straight quarterfinals appearance here, also competed in the 1999 final at the Dusit Resort Pattaya.
Schnyder will face No. 8 Rossana Neffa-de los Rios in Saturday's semifinals. The Paraguayan rallied past Taipei's Su-Wei Hsieh, a qualifier, 1-6, 6-3, 6-4.
The other semifinal pits Slovakia's Henrieta Nagyova, the second seed, against Belarus' Tatiana Poutchek, who advanced to the first tour semifinal of her career.
Nagyova dismissed South African qualifier Liezel Huber, 6-4, 6-3, as she marched into her second semifinal of 2001. The owner of eight career singles titles, Nagyova also advanced to the final four at the Brasil Open.
Poutchek upset No. 5 Tatiana Panova of Russia, 6-2, 6-3. The 22-year-old had only made three quarterfinals before this week, reaching that stage last year at Tashkent, Uzbekistan and Quebec, and in July at Sopot, Poland.