Buckets, hoses and water pistols soak participants carrying portable shrines through eastern Tokyo during the Fukagawa Hachiman Matsuri on Sunday, 16 August.
The footage shows crowds drenching the bearers while firefighters spray them with hoses.
Held once every three years, the main procession featured 54 mikoshi carried along an eight-kilometre route by about 25,000 people.
The festival dates back to 1642, when Tokyo was still known as Edo. Participants say the event requires years of preparation and brings people from different social backgrounds together. Its history also includes a tragedy.
In 1807, Eitai Bridge collapsed under the weight of crowds watching the procession, killing nearly 1,500 people.