The monthly record figure was 24% higher than in March of last year, with Gamstop saying that the most likely reason for the increase was the Cheltenham Festival horse racing event, which ran from 12-15 March.
The organisation said the biggest days for registrations were in the immediate aftermath of the festival.
Since Gamstop launched in April 2018, more than 365,000 people have registered with the self-exclusion scheme for a period of either six months, a year or five years. Almost 330,000 remain excluded from gambling with all licensed operators.
In March 2020, the Gambling Commission made it a licensing condition for all operators to integrate with the scheme, in addition to operating their own self-exclusion schemes.
“Our most recent data shows that, five years after our inception, Gamstop is providing an increasingly important service to potentially vulnerable consumers who want to take a break from gambling,” Gamstop chief executive Fiona Palmer said.
“The record monthly registrations shows that we cannot underestimate the demand for a scheme such as Gamstop. It is extremely important that we continue to raise awareness to make sure that anyone who needs us knows about us.
“We also need to continue to listen to our users and develop and improve the scheme to meet their needs.
The record month came after Gamstop earlier this year revealed that 84,000 consumers registered with the service in 2022, another all-time high.