The Football Association of Wales (FAW) is creating a Football Centre of Excellence at the Vale Resort.
Welsh football's governing body will also be based at the resort and they will leave their Cardiff offices.
The FAW will take over the facility from Pro14 rugby region Cardiff Blues with renovations to the facilities expected to take eight months.
Championship side Cardiff City will remain as a tenant and continue to train at the Vale Resort.
The Football Association of Wales expect to move in by the summer of 2020.
FAW Chief executive Jonathan Ford said: "The FAW's workforce has grown in numbers to meet the requirements of a contemporary football association.
"The FAW has modernised to the extent that it needs office space to reflect that in addition to a more modern way of working which the new FAW headquarter offices at the Vale Resort will allow.
"We at the FAW are very excited for our staff, senior national squads and coaches to be housed at the renowned sporting facilities."
The move will come as a financial relief to Cardiff Blues, whose chairman Alun Jones admitted the region's last accounts "did not make pleasant reading".
The annual report revealed the Blues were paying almost £1.7m to the Vale Resort where their training facilities are based.