The ninth seed needed just 79 minutes to beat the 12th-seeded Ukrainian on Centre Court in temperatures of around 33 degrees, continuing the best Grand Slam run of her career.
Noskova had never progressed beyond the quarter-finals of a major before this year's Wimbledon, but the 21-year-old is now one victory away from winning her first Grand Slam title.
"I just tried to keep cool, be as patient as possible and somehow get the last point," Noskova said after the match.
"When I play my best I know I can play with the best players in the world and have a great result, which is a final in a Grand Slam I guess!"
She will now meet 10th seed Karolina Muchova, who earlier defeated Coco Gauff in a thrilling three-set semi-final.
Looking ahead to the all-Czech final, Noskova praised her opponent.
"Karolina is such a great fighter, such an incredible player, but mainly she is such a great person. I'm glad I can play my first final against her," she said.
The final guarantees another Czech women's singles champion at Wimbledon. Barbora Krejcikova lifted the title in 2024 after Marketa Vondrousova's triumph in 2023, continuing a proud tradition that also includes Petra Kvitova's victories in 2011 and 2014, as well as Jana Novotna's memorable title in 1998.
The semi-final itself was closely contested early on, with both players holding serve in a physical opening set. The breakthrough came at the worst possible moment for Kostyuk, who double-faulted on set point to hand Noskova the advantage.
Noskova carried that momentum into the second set, breaking early for a 3-1 lead. Kostyuk responded by breaking back to keep the contest alive, but the Czech remained calm under pressure and sealed victory when Kostyuk sent a forehand long on match point.
The defeat ended an outstanding run for Kostyuk, who had won 21 of her previous 22 matches. Her only loss before Wimbledon had come against Mirra Andreeva in the French Open semi-finals, but she was again denied a place in her first Grand Slam final.
Noskova's success has been built on outstanding form on grass. She arrived at Wimbledon after winning the Berlin Open, her first title on the surface, and has now won more grass-court matches than any other player on the WTA Tour over the past two seasons.