A string of trucks laden with 170 tonnes of tomatoes rolled through the town's narrow streets, as teams on board distributed their load to surrounding crowds for people to throw at each other during the hour-long festivities.
The iconic fiesta -- which celebrates its 70th anniversary and is billed at "the world's biggest food fight" -- has become a major draw for foreigners, in particular from Britain, Japan and the United States.
"I am going to go three months without eating tomatoes, I'm disgusted but it doesn't matter," a Spanish woman in her 20s, who wore a red T-shirt and whose hair was covered in scarlet mush, told reporters.
One young man could be seen using a plastic pail to scoop up red pulp from the streets and pour it over the heads of others.
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Bunol city hall estimates that only one-fifth of the roughly 22,000 participants this year are from Spain.
"There are countries where maybe people have a harder time expressing their feelings," he told Spanish radio.
"The Japanese for example are very reserved, solemn, and transform themselves when they come here," he added.
Bunol officials estimate that ten per cent of the participants come from Japan.
Organisers recommend revellers squish the tomatoes before throwing them -- "the hit will be less painful" -- wear old clothes and use goggles to protect their eyes from the fruit's acid.
This was the third year non-resident participants were charged 10 euros (USD 11.50) to take part.
A total of 17,000 tickets were sold to foreigners with the rest given away free to locals.
Before ticket sales were introduced the food fight drew over 45,000 revellers to the town.
Young tourists flocked to the town for the festival on specially charted buses from Benidorm and other seaside resorts along Spain's coast, as well as from Madrid and Barcelona.
After the tomato throwing ended, fire trucks hosed down the streets while revellers headed to public showers or jump in a local river to get cleaned up.