Huge waves triggered by the 9.0-magnitude quake - one of the strongest on record - crashed into the northeastern coast, crippling the Fukushima Dai-ichi power plant and forcing more than 160,000 residents to flee as radiation spewed into the air.
Mariko Odawara, a dancer from Hokkaido prefecture, said she visits the coast of Hisanohama every year to mourn for the deaths as she lays down flowers on the coast stones.
"There are people still missing in the sea, so I come here (every year) to pay a floral tribute to the sea, in the hope that it could connect us, who are alive, to people who have not returned from the sea."
At 2:46 p.m. (0546GMT), the exact moment the earthquake struck a decade ago, several dozen people marked the anniversary with a moment of silence to honor the dead in front of a monument for the victims in the town of Namie. Silent prayers were held across the country.