Dublin Marathon organisers say anyone who competed in any of the last three races will be guaranteed a place in the 2020 event.
They've come to the decision after concerns were raised about changing the registration process.
It was announced this week that a lottery system is being introduced, instead of the first-come, first-served online process.
Organisers couldn't meet demand for this year's race, despite an extra 2,500 places being added.
People hoping to take part in the 2020 Dublin marathon will pay €15 to enter the lottery, which opens this Friday.
The fee will be refunded if the applicant is unsuccessful in the draw.
However, the new system has been tweaked after regular competitors complained about the possibility of missing out.
Anyone who took part in one of the last three marathons will receive a special code tomorrow.
They will be guaranteed a place in the 2020 race provided they enter within 72 hours of receiving it.
