The three American men whom French authorities credit with disrupting a potential terror attack on a Paris-bound high-speed train Friday are childhood friends who had all attended California’s Freedom Christian School and often played military games together growing up.

Airman First Class Spencer Stone, Oregon National Guard member Alek Skarlatos and college student Anthony Sadler were tourists trekking through Europe on a planned three-week vacation. They will return home as decorated heroes, following a scheduled visit with French President François Hollande at Élysée Palace, after authorities say they bravely took down a man they say was armed with boxcutters and several guns.

Family members on Saturday said they were grateful that a mass tragedy was averted and that the three friends escaped with their lives.

“We believe God’s providential will worked its way out,” said Mr. Sadler’s father, Anthony Sadler, a Baptist pastor. “I’m just thankful they were there and got things done.”

The three Americans had met in the Netherlands as part of their tour, which they had planned for when Airman Stone was on leave from a U.S. Air Force base in the Azores, when they boarded the train in Amsterdam, family members said.