Isaac Nolting, 12, and Dakotah Zimmer, 13, became fast friends at a Washington, Missouri, swimming pool this summer.
Mutual friends commented that the pair looked like brothers. They soon discovered they were.
Dakotah knew he had a young brother he'd never met. His sibling was adopted as an infant more than 10 years ago to a woman named Dawn.
"That's my mom's name," Isaac told his new friend.
Dakotah told the Missourian he knew his friend, 13 months younger than him, was actually his brother because of one very distinctive feature: "I could tell because of the nose."
Isaac, however, didn't even know he was adopted.
"I just didn't know how to tell him," Issac's adoptive mother, Dawn Nolting, told the Missourian. "I never knew when was the best time. I talked with experts and relatives, but never knew when I should do it."
After his day at the pool with Dakotah, Issac approached his mother with questions about his birth.
"He took my hand and we went back in the bedroom, sat down, and he said, 'Mom, I have something to ask you. Am I adopted?'" Dawn recalled.
"I said, 'What makes you think that?' and he said, 'I think I found my brother.'"
Dawn told her son it was true. They both started crying.
"I just cried and cried and cried," Isaac told TODAY.com. "I was so happy that I had a brother. I always asked for one."
The boys' birth parents are now passed away. Dakotah lives with his grandmother, Debi Bay.
"I knew it was gonna happen sooner or later," said Debi Bay, 56. "It didn't surprise me that much. I'm just surprised the way they ran into each other. I'm glad they got to meet."
Their mother, a teenager overwhelmed by two babies, gave up Isaac when he was just a couple weeks old. At first, Dawn cared for Isaac to give the new mom "a break." Isaac's mom would call and visit often — but she never took him home.
The adoption was finalized when he was 18 months old.
The reunited brothers celebrated their birthdays together this fall. They have weekend sleepovers, hang out after school, and will spend the holidays together, too.
"You can just tell they're brothers," Dawn told TODAY.com. "It's the strongest bond that I've ever seen. It's like they were never separated. For being apart for 10 years and 20 minutes away, they picked up right where they left off."
"A lot of people are happy," Dawn told the Missourian. "We're planning a big celebration at the holidays this year."