Nadal demolished Austrian pretender and sixth seed Dominic Thiem 6-3, 6-4, 6-0 to return to the final at Roland Garros for the first time since the last of his nine titles in 2014.
Wawrinka became the oldest finalist in Paris in 44 years with a thrilling 6-7 (6/8), 6-3, 5-7, 7-6 (7/3), 6-1 win over world number one Murray.
"I've played a very good event, played well in all the matches and today was no exception," said Nadal, who has lost just 29 games in reaching Sunday's championship match.
"I started a bit more nervous, but then I played well.
"It's true that Dominic played with more mistakes than usual today, but it was windy."
Nadal is bidding to become the first man to win 10 titles at a single Grand Slam and leads the head-to-head with Wawrinka 15-3.
"I always say the same but it's true. Nine or 10, it's only 10 percent more. It's true 10 is a beautiful number, nine is my favourite, but if I win it will become 10."
However, he will be mindful of another upset after the Swiss stunned an injury-hit Nadal three years ago to claim the Australian Open crown.
"I have been playing a great event. But Stan is playing unbelievable," said Nadal, who despite his imposing record has split the past six meetings with Wawrinka.
"It will be a super hard final and I will need to play at my very best."
Nadal withstood a shaky start before reeling off four games in succession to subdue Thiem, who was looking to be just the second Austrian finalist at a Slam after 1995 French Open winner Thomas Muster.
Thiem is the only player to defeat Nadal on clay this season, but the fourth seed barely gave his rival a sniff and conceded just nine points in a chastening final set.
US Open champion Wawrinka, 32, triumphed in a pulsating four hour 34 minute battle of shotmaking and endurance and will target a fourth Slam title this weekend.
For Murray, his wait to become Britain's first men's champion in Paris since Fred Perry in 1935 goes on.
"It's incredible to be in another Roland Garros final," said Wawrinka, the oldest finalist since 33-year-old Niki Pilic was runner-up in 1973.
His win avenged defeat to Murray at the same stage in 2016 and the Swiss suggested the Briton was nowhere near that form on Friday.
"Last year he was much more aggressive but last year he was stronger," said Wawrinka after reaching his fourth final at the majors.
"Today I think he's less confident. He played a bit less fast. He was a little more hesitant, and that gave me a bit more time to actually install my game."
But Wawrinka is in no doubt as to the nature of the obstacle that stands in his way of a second Roland Garros triumph.
"I think to play Rafa on clay in French Open in a final is probably the biggest challenge you can have in tennis. He's the best player ever on clay."
Murray, the 2016 runner-up to Novak Djokovic, admitted that Wawrinka was the stronger player in the end.
"I tried to keep fighting, but he played well at the end," said Murray.
"I was a tiebreak from getting to the final in a tournament which I came into struggling."
For Thiem, it was a disappointing end to a tournament which had seen him defeat Djokovic in the quarter-finals.
"I was not on top of my game and the result everybody saw," he said.
"It's nice to be in the semis again, but I'm really disappointed because I just couldn't play the way I wanted to. I don't know why yet, so I have to find some reasons."