Panamanian painter Olga Sinclair was behind the massive work of art depicting the canal locks at the El Prado promenade in Panama City yesterday.
She said she wanted to break the record to encourage "Panama to dream big" and show "that our children can touch the sky with their hands."
The previous record had been held by a group in Saudi Arabia, when some 3,860 participants painted together.
"I was afraid to get dirty, but now I see it was fun," one girl told a local paper.
The 80-kilometre canal, which handles five per cent of global maritime trade, was inaugurated on August 15, 1914.
It is currently undergoing an expansion to make it big enough to handle new cargo ships that can carry 12,000 containers, but work has been disrupted by a financial dispute.