CAMBRIDGE, Mass. — Captains of a Boston “duck boat” rescued a father and son from the Charles River after the toddler tumbled into the water followed by his father on Monday, officials said.

The Boston Duck Tours boat, which take tourists both on water and on land, was participating in quarterly safety drills when it retrieved the pair from the water. The boy was taken to a hospital as a precaution Monday morning, the Cambridge Fire Department said.

“This is crazy. This is happening while we’re doing training,” Michael Rosario, one of the captains, recounted to reporters. “Now we’re doing real-life rescue.”

The boy, who’s under 2, got past safety railing and fell into the river behind the Royal Sonesta, a riverfront hotel in Cambridge, according to Massachusetts State Police. His father quickly jumped in after him.

Photos showed both of them in the water with the father clinging to a rock face with one arm while holding his son with the other.

Rosario and co-captain Kevin O’Neil tossed out a safety ring, maneuvered close to them and dropped a ladder. Once both were safely aboard, they motored to the dock in Cambridge where they were met by first responders.

“We were happy to be in the right place at the right time,” said Tom Vigna, director of marketing for Boston Duck Tours.