Unlike professional canoers, these folks have to make their own canoes.
Each team gets two cardboard boxes and a roll of tape.
They have only 40 minutes to build a canoe. Then, they must paddle it across a lake.
Seventeen teams from around Japan are competing.
People in the town of Sakaide created the event to highlight the fun of canoeing in a nearby lake.
Even the mayor joined in, but he didn't have much luck.
He says it was over in a flash. He says the most difficult part is just getting in.
The mayor says he wants more people to start canoeing.
Most of the participants had never even been in a canoe, not to mention a cardboard one.
In the end, only four teams made it the full distance, but that didn't stop them from having a blast.