Their master, Mr Donaldson, we suspect that's him on the right, looks like a stern taskmaster. Having said that, you wouldn't want to mess with the wee mustachioed fellow on the left either.
At a time when Glasgow boys were still want to dive into the Clyde, the Cart, the Kelvin or the Forth and Clyde Canal, learning to swim was a vital skill and, across the city, pupils plunged in at the deep end to prove their prowess.
Brave as they were, within a few years many of these boys would have received their call-up papers and gone off to the First World War.
Here's hoping that most of them made it home to Glasgow, to build careers, raise families, and teach their own wee ones how to swim.