The event is open to all comers.

所有人均可参加这项比赛。

《牛津词典》

Women had been eager participants in the early years of flying, when things were disorganized and open to all comers.

NPR: Excerpt: 'When Everything Changed'

To preserve the illusion of a track open to all comers, France has made several moves to support smaller one- and two-car teams.

FORBES: Magazine Article

That has changed very quickly and dramatically with the sudden availability of adventure races open to all comers in every corner of the country.

FORBES: New Year's Fitness Resolution: Try Adventure Or Obstacle Racing?