Tanner Buchanan and Mary Mouser’s Relationship: All About the Cobra Kai Stars’ Romance (and Their Surprise Engagement Announcement!)

Cobra Kai fans have been shipping Tanner Buchanan and Mary Mouser’s characters for years. Little did they know, there was a real-life romance brewing between the costars.

Since becoming castmates on the hit Netflix martial arts series in 2018, Buchanan and Mouser have maintained a sweet friendship off-screen. They’ve dressed up in matching costumes for Halloween, played laser tag and supported each other’s work in different projects.

But Buchanan and Mouser never hinted at their relationship being more than a friendship — until they shared a kiss on the red carpet for a Cobra Kai series finale event in February 2025.

The couple, who were photographed holding up matching rings on their left hands, confirmed their relationship and engagement the following day. 

“We’re so happy to finally share that we’re engaged,” Buchanan and Mouser captioned a joint Instagram post. “This is such a special moment in our lives, the closing of one chapter and celebrating the continuation of another.” 

From their on-screen romance to their off-screen friendship, here’s everything to know about Tanner Buchanan and Mary Mouser’s relationship.

They’ve starred in Cobra Kai together since 2018

Buchanan and Mouser have starred in Cobra Kai — Netflix’s hit spinoff series of the classic martial arts film The Karate Kid — since season 1 premiered in 2018. Mouser plays Samantha “Sam” LaRusso, the daughter of Daniel LaRusso (Ralph Macchio), and Buchanan plays bad boy Robby Keene. 

On-screen, their characters had a brief romantic relationship in season 2, but it didn’t last. The Cobra Kai series concluded with season 6, which premiered its final episodes on Netflix in February 2025.

Mouser described them as “besties”

Up until 2025, Mouser and Buchanan maintained that they were just really good friends. In 2019, the actress wished her costar a happy birthday on Instagram with a multi-photo post and a long caption in which she referred to them as “besties."

“You are the most kind and beautiful soul of all time, I am so grateful to know you and adore you!” Mouser wrote. “You’re the greatest and you deserve the greatest! thank you with all my heart for everything bestest budddddddy! (even for the times where you get on my last freakin nerve!)”

They share a love for Disney

In addition to knowing some killer martial arts moves, the Cobra Kai stars also share another interest: Disney. Mouser and Buchanan spent the 2022 holiday season together visiting their favorite theme park in multiple countries. 

The couple spent a day in Disneyland in California in November 2022 and visited Disneyland Paris in France the next month. During the latter of those trips, they cuddled up for photos in matching Mickey Mouse sweaters.

Buchanan said he was nervous to kiss Mouser on Cobra Kai

Even though a primary role in Cobra Kai came with its fair share of intense stunts and fight scenes, Buchanan said he was more nervous to kiss his costar-turned-fiancée.

In a 2020 interview with Interview Magazine, the He’s All That actor told Macchio that the romantic scenes caused him “the most anxiety.”

“You could talk to Mary [Mouser] about this because she and I are such good friends,” said Buchanan. “When we had our first kiss scene in season two, they were asking us, ‘Are you ready?’ My heart was pounding, I was shaking. It just feels weird to go to that place, because we’re such good friends.”

They confirmed their relationship — and announced their engagement — in February 2025

On Feb. 12, 2025, Buchanan and Mouser attended the Netflix series finale event for Cobra Kai. While posing for photos on the red carpet, they kissed and showed off a pair of matching rings on their left hands. Those photos not only confirmed that their relationship had turned romantic but also ignited engagement rumors.

Buchanan and Mouser then confirmed those rumors in a joint Instagram post the following day. The announcement featured photos of them walking hand-in-hand before the event and drinking glasses of champagne.

“We’re so grateful for the love and support,” they wrote in the caption, “and though we’re partial to having our private moments, we’re excited to share this check-in to our world 🖤.”