Six-time Grand Slam champion Swiatek was never in serious trouble as she beat Romania's Sorana Cirstea 6-3, 6-2 in Seoul.
World number two Swiatek was stunned in straight sets by eventual finalist Amanda Anisimova in the last eight a fortnight ago at New York, where she triumphed in 2022.
"For sure, the conditions are much different from our last tournament," the Pole told the crowd in the South Korean capital, where there has been heavy rain this week.
"Happy that I could adjust quickly. I really love it here, it's beautiful when it's not raining, so happy to be here."
Swiatek, whose father Tomasz competed in rowing at the 1988 Seoul Olympics, sealed the first set against Cirstea in 49 minutes on her sixth set point.
The top seed carried that momentum into the second set, breaking the Romanian immediately and, despite a few wobbles, Swiatek sealed the match with minimum fuss.
Krejcikova battles past Raducanu
The 24-year-old, who is chasing a 25th WTA singles title, will play Krejcikova after the unseeded Czech battled back to beat Emma Raducanu 4-6, 7-6(10), 6-1.
Britain's Raducanu, the 2021 US Open champion and eighth seed in Seoul, squandered three match points as two-time former major champion Krejcikova prevailed in a late-night thriller.
Also into the quarter-finals on Friday is second seed Ekaterina Alexandrova, who plays unseeded Ella Seidel of Germany.