I tried to get out and couldn't. I was trying to get out and skidded, my foot got stuck, in the water. I had trouble getting out.
Hundreds were gathered in the port of Vigo just after midnight when part of the wooden pier suddenly caved in.
There were no known fatalities from the incident, but Xunta Galicia's health department told CNN that nine people were still hospitalized with injuries resulting from the accident. People landed on top of me.
A friend described the scene as "horrible, chaos, panic", adding: "I saw a family and the little girl was saying to her dad, 'If we die here, I love you'".
In a tweet, he wished "strength" to the injured and advised anyone anxious about friends or relatives to contact an emergency information point set up by festival organisers.
Abel Caballero, the mayor of Vigo, ruled out the possibility that they could have been trapped under the collapsed platform, as rescuers scanned the area twice with thermal cameras, El Pais reported.
But the head of the city's port authority told a local radio station it was likely "excessive weight" that caused the boardwalk, held up by concrete pillars, to give way, and that there may have been structural issues, USA Today reports.
The annual festival, which bills itself as the "most important urban sports event in southern Europe", draws some 160,000 people to Vigo, a city of around 300,000 residents.
Nadal not to play 2018 Cincinnati Open
I am also sad for those wonderful fans in Cincy and around who always gave me great support. "I am sure I'll see them next year". The Spanish world number one concluded victory with a forehand victor deep into the corner.