The eighth seed seized control from the outset and never loosened her grip on the contest, overwhelming Kostyuk with her depth and aggression on Court Philippe Chatrier to set up a title clash against compatriot Diana Shnaider or Polish qualifier Maja Chwalinska.
As has become customary for Ukrainian players since Russia's invasion of their country in 2022, Kostyuk did not pose for the traditional pre-match photograph with her opponent and there was no handshake at the net before or after the match.
Andreeva, 19, raced into a 4-0 lead in the opening set and barely looked back in the third meeting between the two players, the Ukrainian having won the first two.
Kostyuk briefly threatened to make a contest of it in the second set, but the Russian swiftly snuffed out any hopes of a comeback before serving out the match to complete a dominant display.
"I'm still very nervous, very nervous coming to this match as she's had an amazing season, she hadn't lost on clay, so that put pressure," said Andreeva.
"She's an amazing player, a tough opponent, so I'm super happy with the way I played. I'm happy I got revenge for the Madrid final, and to reach my first Grand Slam final.
"All of these feelings combined, I've never felt anything like this, I'm very excited about the last match here in Paris."
Kostyuk seemed to struggle with early nerves and windy conditions, handing her opponent the first break with a double fault and an unforced backhand error while Andreeva picked up steam.
The Ukrainian was out of sorts but briefly put up a fight in the second set when she broke back for 4-3, only to drop serve in the next game and continue to pepper the court with unforced errors.
A final forehand wide gave Andreeva a deserved win after one hour and 16 minutes of a one-sided encounter.
"The conditions were tough, very windy, I couldn't understand which direction it was going, but I'm happy I was able to stay focused," said Andreeva after both players had continued to play when the roof was being closed.
"I was ready to accept anything that happens. It felt like a day when anything could happen. I told myself I would fight, and if she had to win she would have to work for it. With this mindset, I ended up winning and I'm very happy."